{"id":121,"date":"2020-12-04T10:19:22","date_gmt":"2020-12-04T04:19:22","guid":{"rendered":"http:\/\/www.dreamflier.net\/wordpress\/?p=121"},"modified":"2021-01-14T19:51:51","modified_gmt":"2021-01-14T13:51:51","slug":"django%e7%9a%84%e6%9f%a5%e8%af%a2%e6%93%8d%e4%bd%9c","status":"publish","type":"post","link":"http:\/\/www.jichangqing.net\/wordpress\/?p=121","title":{"rendered":"django\u7684\u67e5\u8be2\u64cd\u4f5c"},"content":{"rendered":"

\u67e5\u8be2\u64cd\u4f5c<\/h1>\n

https:\/\/www.liujiangblog.com\/course\/django\/129<\/p>\n

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\u67e5\u8be2\u64cd\u4f5c\u662fDjango\u7684ORM\u6846\u67b6\u4e2d\u6700\u91cd\u8981\u7684\u5185\u5bb9\u4e4b\u4e00\u3002\u6211\u4eec\u5efa\u7acb\u6a21\u578b\u3001\u4fdd\u5b58\u6570\u636e\u4e3a\u7684\u5c31\u662f\u5728\u9700\u8981\u7684\u65f6\u5019\u53ef\u4ee5\u67e5\u8be2\u5f97\u5230\u6570\u636e\u3002Django\u81ea\u52a8\u4e3a\u6240\u6709\u7684\u6a21\u578b\u63d0\u4f9b\u4e86\u4e00\u5957\u5b8c\u5584\u3001\u65b9\u4fbf\u3001\u9ad8\u6548\u7684API\uff0c\u4e00\u4e9b\u91cd\u8981\u7684\uff0c\u6211\u4eec\u8981\u80cc\u4e0b\u6765\uff0c\u4e00\u4e9b\u4e0d\u5e38\u7528\u7684\uff0c\u8981\u6709\u5370\u8c61\uff0c\u4f7f\u7528\u7684\u65f6\u5019\u53ef\u4ee5\u5feb\u901f\u67e5\u627e\u53c2\u8003\u624b\u518c\u3002<\/p>\n

\n

\u672c\u8282\u7684\u5185\u5bb9\u57fa\u4e8e\u5982\u4e0b\u7684\u4e00\u4e2a\u535a\u5ba2\u5e94\u7528\u6a21\u578b\uff1a<\/p>\n

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from<\/span> django.db<\/span> import<\/span> models<\/span>\r\n\r\nclass<\/span> Blog<\/span>(<\/span>models<\/span>.<\/span>Model<\/span>):<\/span>\r\n    name<\/span> =<\/span> models<\/span>.<\/span>CharField<\/span>(<\/span>max_length<\/span>=<\/span>100<\/span>)<\/span>\r\n    tagline<\/span> =<\/span> models<\/span>.<\/span>TextField<\/span>()<\/span>\r\n\r\n    def<\/span> __str__<\/span>(<\/span>self<\/span>):<\/span>\r\n        return<\/span> self<\/span>.<\/span>name<\/span>\r\n\r\nclass<\/span> Author<\/span>(<\/span>models<\/span>.<\/span>Model<\/span>):<\/span>\r\n    name<\/span> =<\/span> models<\/span>.<\/span>CharField<\/span>(<\/span>max_length<\/span>=<\/span>200<\/span>)<\/span>\r\n    email<\/span> =<\/span> models<\/span>.<\/span>EmailField<\/span>()<\/span>\r\n\r\n    def<\/span> __str__<\/span>(<\/span>self<\/span>):<\/span>\r\n        return<\/span> self<\/span>.<\/span>name<\/span>\r\n\r\nclass<\/span> Entry<\/span>(<\/span>models<\/span>.<\/span>Model<\/span>):<\/span>\r\n    blog<\/span> =<\/span> models<\/span>.<\/span>ForeignKey<\/span>(<\/span>Blog<\/span>,<\/span> on_delete<\/span>=<\/span>models<\/span>.<\/span>CASCADE<\/span>)<\/span>\r\n    headline<\/span> =<\/span> models<\/span>.<\/span>CharField<\/span>(<\/span>max_length<\/span>=<\/span>255<\/span>)<\/span>\r\n    body_text<\/span> =<\/span> models<\/span>.<\/span>TextField<\/span>()<\/span>\r\n    pub_date<\/span> =<\/span> models<\/span>.<\/span>DateField<\/span>()<\/span>\r\n    mod_date<\/span> =<\/span> models<\/span>.<\/span>DateField<\/span>()<\/span>\r\n    authors<\/span> =<\/span> models<\/span>.<\/span>ManyToManyField<\/span>(<\/span>Author<\/span>)<\/span>\r\n    number_of_comments<\/span> =<\/span> models<\/span>.<\/span>IntegerField<\/span>()<\/span>\r\n    number_of_pingbacks<\/span> =<\/span> models<\/span>.<\/span>IntegerField<\/span>()<\/span>\r\n    rating<\/span> =<\/span> models<\/span>.<\/span>IntegerField<\/span>()<\/span>\r\n\r\n    def<\/span> __str__<\/span>(<\/span>self<\/span>):<\/span>\r\n        return<\/span> self<\/span>.<\/span>headline<\/span>\r\n<\/pre>\n<\/div>\n
\u4e00\u3001\u521b\u5efa\u5bf9\u8c61<\/h1>\n
\u5047\u8bbe\u6a21\u578b\u4f4d\u4e8emysite\/blog\/models.py<\/code>\u6587\u4ef6\u4e2d\u3002<\/p>\n
\u521b\u5efa\u4e00\u4e2a\u6a21\u578b\u5b9e\u4f8b\uff0c\u4e5f\u5c31\u662f\u4e00\u6761\u6570\u636e\u5e93\u8bb0\u5f55\uff0c\u6700\u4e00\u822c\u7684\u65b9\u5f0f\u662f\u4f7f\u7528\u6a21\u578b\u7c7b\u7684\u5b9e\u4f8b\u5316\u6784\u9020\u65b9\u6cd5\uff1a<\/p>\n
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>>><\/span> from<\/span> blog.models<\/span> import<\/span> Blog<\/span>\r\n>>><\/span> b<\/span> =<\/span> Blog<\/span>(<\/span>name<\/span>=<\/span>'Beatles Blog'<\/span>,<\/span> tagline<\/span>=<\/span>'All the latest Beatles news.'<\/span>)<\/span>\r\n>>><\/span> b<\/span>.<\/span>save<\/span>()<\/span>\r\n<\/pre>\n<\/div>\n
\u5728\u540e\u53f0\uff0c\u8fd9\u4f1a\u6267\u884c\u4e00\u6761SQL\u7684INSERT\u8bed\u53e5\u3002\u5982\u679c\u4f60\u4e0d\u663e\u5f0f\u5730\u8c03\u7528save()\u65b9\u6cd5\uff0cDjango\u4e0d\u4f1a\u7acb\u523b\u5c06\u8be5\u64cd\u4f5c\u53cd\u6620\u5230\u6570\u636e\u5e93\u4e2d\u3002save()\u65b9\u6cd5\u6ca1\u6709\u8fd4\u56de\u503c\uff0c\u5e76\u4e14\u53ef\u4ee5\u63a5\u53d7\u4e00\u4e9b\u989d\u5916\u7684\u53c2\u6570\u3002<\/p>\n
\u63d0\u9192\uff1a\u5728\u4ee3\u7801\u4e2d\u6216\u8005shell\u4e2d\u4f7f\u7528API\u7684\u65b9\u5f0f\u76f4\u63a5\u521b\u5efa\u6a21\u578b\u5b9e\u4f8b\u662f\u4e0d\u4f1a\u5f15\u53d1\u6570\u636e\u9a8c\u8bc1\u7684\u3002\u5bf9\u4e8eBlog\u6a21\u578b\uff0cname\u548ctagline\u90fd\u662f\u5fc5\u987b\u586b\u5199\u7684\u5b57\u6bb5\u3002\u4f46\u662f\u4f60\u5b8c\u5168\u53ef\u4ee5\u6267\u884cb = Blog(name=’liujiangblog’)\uff0c\u4e0d\u63d0\u4f9btagline\u7684\u503c\uff0c\u7136\u540esave\u5230\u6570\u636e\u5e93\u3002\u800c\u5728\u8868\u5355\u4e2d\uff0c\u6bd4\u5982admin\u540e\u53f0\uff0c\u8fd9\u662f\u4e0d\u884c\u7684\uff0c\u56e0\u4e3aDjango\u7684\u8868\u5355\u9ed8\u8ba4\u8981\u8fdb\u884c\u6570\u636e\u5b8c\u6574\u6027\u3001\u5408\u6cd5\u6027\u9a8c\u8bc1\u3002<\/p><\/blockquote>\n
\u5982\u679c\u60f3\u8981\u4e00\u884c\u4ee3\u7801\u5b8c\u6210\u4e0a\u9762\u7684\u64cd\u4f5c\uff0c\u8bf7\u4f7f\u7528creat()<\/code>\u65b9\u6cd5\uff0c\u5b83\u53ef\u4ee5\u7701\u7565save\u7684\u6b65\u9aa4\uff0c\u6bd4\u5982\uff1a<\/p>\n
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b<\/span> =<\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>'\u5218\u6c5f\u7684\u535a\u5ba2'<\/span>,<\/span> tagline<\/span>=<\/span>'\u4e3b\u9875\u4f4d\u4e8eliujiangblog.com.'<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
\u6709\u5f88\u591a\u4eba\u559c\u6b22\u5728\u6a21\u578b\u7684\u521d\u59cb\u5316\u4e0a\u505a\u6587\u7ae0\uff0c\u5b9e\u73b0\u4e00\u4e9b\u989d\u5916\u7684\u4e1a\u52a1\u9700\u6c42\uff0c\u5e38\u89c1\u7684\u505a\u6cd5\u662f\u81ea\u5b9a\u4e49__init__<\/code>\u65b9\u6cd5\u3002\u8fd9\u4e0d\u597d\uff0c\u5bb9\u6613\u6253\u65adDjango\u6e90\u7801\u7684\u8c03\u7528\u94fe\uff0c\u5b58\u5728\u6f0f\u6d1e\u3002\u66f4\u63a8\u8350\u7684\u662f\u4e0b\u9762\u4e24\u79cd\u65b9\u6cd5\u3002<\/p>\n
\u7b2c\u4e00\u79cd\u65b9\u6cd5\uff1a\u4e3a\u6a21\u578b\u589e\u52a0create\u7c7b\u65b9\u6cd5\uff0c\u5728\u5176\u4e2d\u5939\u585e\u4f60\u7684\u4ee3\u7801\uff1a<\/p>\n
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from<\/span> django.db<\/span> import<\/span> models<\/span>\r\n\r\nclass<\/span> Book<\/span>(<\/span>models<\/span>.<\/span>Model<\/span>):<\/span>\r\n    title<\/span> =<\/span> models<\/span>.<\/span>CharField<\/span>(<\/span>max_length<\/span>=<\/span>100<\/span>)<\/span>\r\n\r\n    @classmethod<\/span>\r\n    def<\/span> create<\/span>(<\/span>cls<\/span>,<\/span> title<\/span>):<\/span>\r\n        book<\/span> =<\/span> cls<\/span>(<\/span>title<\/span>=<\/span>title<\/span>)<\/span>\r\n        # \u5c06\u4f60\u7684\u4e2a\u4eba\u4ee3\u7801\u653e\u5728\u8fd9\u91cc<\/span>\r\n        print<\/span>(<\/span>'\u6d4b\u8bd5\u4e00\u4e0b\u662f\u5426\u5de5\u4f5c\u6b63\u5e38'<\/span>)<\/span>\r\n        return<\/span> book<\/span>\r\n\r\nbook<\/span> =<\/span> Book<\/span>.<\/span>create<\/span>(<\/span>\"liujiangblog.com\"<\/span>)<\/span>   # \u6ce8\u610f\uff0c\u6539\u4e3a\u4f7f\u7528created\u65b9\u6cd5\u521b\u5efaBook\u5bf9\u8c61<\/span>\r\nbook<\/span>.<\/span>save<\/span>()<\/span>           # \u53ea\u6709\u8c03\u7528save\u540e\u624d\u80fd\u4fdd\u5b58\u5230\u6570\u636e\u5e93<\/span>\r\n<\/pre>\n<\/div>\n
\u7b2c\u4e8c\u79cd\u65b9\u6cd5\uff1a\u81ea\u5b9a\u4e49\u7ba1\u7406\u5668\uff0c\u5e76\u5728\u5176\u4e2d\u6dfb\u52a0\u521b\u5efa\u5bf9\u8c61\u7684\u65b9\u6cd5\uff0c\u63a8\u8350\uff01<\/p>\n
\n
class<\/span> BookManager<\/span>(<\/span>models<\/span>.<\/span>Manager<\/span>):<\/span>   # \u7ee7\u627f\u9ed8\u8ba4\u7684\u7ba1\u7406\u5668<\/span>\r\n    def<\/span> create_book<\/span>(<\/span>self<\/span>,<\/span> title<\/span>):<\/span>\r\n        book<\/span> =<\/span> self<\/span>.<\/span>create<\/span>(<\/span>title<\/span>=<\/span>title<\/span>)<\/span>\r\n        # \u5c06\u4f60\u7684\u4e2a\u4eba\u4ee3\u7801\u653e\u5728\u8fd9\u91cc<\/span>\r\n        print<\/span>(<\/span>'\u6d4b\u8bd5\u4e00\u4e0b\u662f\u5426\u5de5\u4f5c\u6b63\u5e38'<\/span>)<\/span>\r\n        return<\/span> book<\/span>\r\n\r\nclass<\/span> Book<\/span>(<\/span>models<\/span>.<\/span>Model<\/span>):<\/span>\r\n    title<\/span> =<\/span> models<\/span>.<\/span>CharField<\/span>(<\/span>max_length<\/span>=<\/span>100<\/span>)<\/span>\r\n\r\n    objects<\/span> =<\/span> BookManager<\/span>()<\/span>   # \u8d4b\u503cobjects<\/span>\r\n\r\nbook<\/span> =<\/span> Book<\/span>.<\/span>objects<\/span>.<\/span>create_book<\/span>(<\/span>\"liujiangblog.com\"<\/span>)<\/span>   #\u6539\u4e3a\u4f7f\u7528create_book\u65b9\u6cd5\u521b\u5efa\u5bf9\u8c61<\/span>\r\n<\/pre>\n<\/div>\n
\u4e8c\u3001\u4fee\u6539\u5bf9\u8c61\u5e76\u4fdd\u5b58<\/h1>\n
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Model<\/span>.<\/span>save<\/span>(<\/span>force_insert<\/span>=<\/span>False<\/span>,<\/span> force_update<\/span>=<\/span>False<\/span>,<\/span> using<\/span>=<\/span>DEFAULT_DB_ALIAS<\/span>,<\/span> update_fields<\/span>=<\/span>None<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
\u4f7f\u7528save()\u65b9\u6cd5\uff0c\u4fdd\u5b58\u5bf9\u6570\u636e\u5e93\u5185\u5df2\u6709\u5bf9\u8c61\u7684\u4fee\u6539\u3002\u4f8b\u5982\u5982\u679c\u5df2\u7ecf\u5b58\u5728b5\u5bf9\u8c61\u5728\u6570\u636e\u5e93\u5185\uff1a<\/p>\n
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>>><\/span> b5<\/span>.<\/span>name<\/span> =<\/span> 'New name'<\/span>\r\n>>><\/span> b5<\/span>.<\/span>save<\/span>()<\/span>\r\n<\/pre>\n<\/div>\n
\u5728\u540e\u53f0\uff0c\u8fd9\u4f1a\u8fd0\u884c\u4e00\u6761SQL\u7684UPDATE\u8bed\u53e5\u3002\u5982\u679c\u4f60\u4e0d\u663e\u5f0f\u5730\u8c03\u7528save()\u65b9\u6cd5\uff0cDjango\u4e0d\u4f1a\u7acb\u523b\u5c06\u8be5\u64cd\u4f5c\u53cd\u6620\u5230\u6570\u636e\u5e93\u4e2d\u3002<\/p>\n
\u6211\u4eec\u5f80\u5f80\u4f1a\u91cd\u5199save\u65b9\u6cd5\uff0c\u6dfb\u52a0\u81ea\u5df1\u7684\u4e1a\u52a1\u903b\u8f91\uff0c\u7136\u540e\u5728\u5176\u4e2d\u8c03\u7528\u539f\u6765\u7684save\u65b9\u6cd5\uff0c\u4fdd\u8bc1Django\u57fa\u672c\u5de5\u4f5c\u673a\u5236\u6b63\u5e38\u3002\u6bd4\u5982\u4e0b\u9762\u7684\u4f8b\u5b50\uff1a<\/p>\n
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from<\/span> django.db<\/span> import<\/span> models<\/span>\r\n\r\nclass<\/span> Blog<\/span>(<\/span>models<\/span>.<\/span>Model<\/span>):<\/span>\r\n    name<\/span> =<\/span> models<\/span>.<\/span>CharField<\/span>(<\/span>max_length<\/span>=<\/span>100<\/span>)<\/span>\r\n    tagline<\/span> =<\/span> models<\/span>.<\/span>TextField<\/span>()<\/span>\r\n\r\n    def<\/span> save<\/span>(<\/span>self<\/span>,<\/span> *<\/span>args<\/span>,<\/span> **<\/span>kwargs<\/span>):<\/span>\r\n        do_something<\/span>()<\/span>   # \u4fdd\u5b58\u524d\u505a\u70b9\u79c1\u6d3b<\/span>\r\n        super<\/span>()<\/span>.<\/span>save<\/span>(<\/span>*<\/span>args<\/span>,<\/span> **<\/span>kwargs<\/span>)<\/span>  # \u4e00\u5b9a\u4e0d\u8981\u5fd8\u8bb0\u8fd9\u884c\u4ee3\u7801<\/span>\r\n        do_something_else<\/span>()<\/span>  # \u4fdd\u5b58\u540e\u53c8\u52a0\u585e\u70b9\u4e1c\u897f<\/span>\r\n<\/pre>\n<\/div>\n
\u8fd9\u6837\uff0c\u4efb\u4f55\u4e00\u7bc7\u535a\u5ba2\u5728\u4fdd\u5b58\u524d\u540e\u90fd\u4f1a\u6267\u884c\u4e00\u4e9b\u989d\u5916\u7684\u4ee3\u7801\u3002<\/p>\n
\u6ce8\u610f\uff0c\u5343\u4e07\u4e0d\u8981\u5fd8\u8bb0super().save(*args, **kwargs)<\/code>\uff0c\u8fd9\u884c\u786e\u4fdd\u4e86Django\u6e90\u7801\u4e2d\u5173\u4e8esave\u65b9\u6cd5\u7684\u4ee3\u7801\u4f1a\u4f9d\u7136\u88ab\u6267\u884c\u3002\u6211\u4eec\u662f\u5939\u5e26\u79c1\u8d27\uff0c\u4e0d\u662f\u4e0d\u5e72\u6d3b\u3002<\/p>\n
\u4e0b\u9762\u7684\u4f8b\u5b50\u5219\u662f\u5bf9\u535a\u5ba2\u540d\u5b57\u505a\u9650\u5236\uff0c\u53ea\u6709\u5218\u6c5f\u7684\u535a\u5ba2\u624d\u53ef\u4ee5\u4fdd\u5b58\uff1a<\/p>\n
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from<\/span> django.db<\/span> import<\/span> models<\/span>\r\n\r\nclass<\/span> Blog<\/span>(<\/span>models<\/span>.<\/span>Model<\/span>):<\/span>\r\n    name<\/span> =<\/span> models<\/span>.<\/span>CharField<\/span>(<\/span>max_length<\/span>=<\/span>100<\/span>)<\/span>\r\n    tagline<\/span> =<\/span> models<\/span>.<\/span>TextField<\/span>()<\/span>\r\n\r\n    def<\/span> save<\/span>(<\/span>self<\/span>,<\/span> *<\/span>args<\/span>,<\/span> **<\/span>kwargs<\/span>):<\/span>\r\n        if<\/span> self<\/span>.<\/span>name<\/span> !=<\/span> \"\u5218\u6c5f\u7684\u535a\u5ba2\"<\/span>:<\/span>\r\n            return<\/span> # \u53ea\u6709\u5218\u6c5f\u7684\u535a\u5ba2\u624d\u53ef\u4ee5\u4fdd\u5b58<\/span>\r\n        else<\/span>:<\/span>\r\n            super<\/span>()<\/span>.<\/span>save<\/span>(<\/span>*<\/span>args<\/span>,<\/span> **<\/span>kwargs<\/span>)<\/span>  # \u8c03\u7528\u771f\u6b63\u7684save\u65b9\u6cd5<\/span>\r\n<\/pre>\n<\/div>\n
*args, **kwargs<\/code>\u7684\u53c2\u6570\u8bbe\u8ba1\uff0c\u786e\u4fdd\u6211\u4eec\u81ea\u5b9a\u4e49\u7684save\u65b9\u6cd5\u662f\u4e2a\u4e07\u91d1\u6cb9\uff0c\u4e0d\u8bbaDjango\u6e90\u7801\u4e2d\u7684save\u65b9\u6cd5\u7684\u53c2\u6570\u600e\u4e48\u53d8\uff0c\u6211\u4eec\u81ea\u5df1\u7684save\u65b9\u6cd5\u4e0d\u4f1a\u56e0\u4e3a\u53c2\u6570\u5b9a\u4e49\u7684\u4e0d\u6b63\u786e\u800c\u51fa\u73b0bug\u3002<\/p>\n
\u6b64\u5916\uff0c\u6a21\u578b\u5b9e\u4f8b\u7684\u4fdd\u5b58\u8fc7\u7a0b\u6709\u4e00\u4e9b\u503c\u5f97\u63a2\u7a76\u7684\u7ec6\u8282\u3002<\/p>\n
\u6267\u884csave\u65b9\u6cd5\u540e\uff0cDjango\u624d\u4f1a\u771f\u6b63\u4e3a\u5bf9\u8c61\u8bbe\u7f6e\u81ea\u589e\u4e3b\u952e\u7684\u503c\uff1a<\/p>\n
\n
>>><\/span> b2<\/span> =<\/span> Blog<\/span>(<\/span>name<\/span>=<\/span>'Cheddar Talk'<\/span>,<\/span> tagline<\/span>=<\/span>'Thoughts on cheese.'<\/span>)<\/span>\r\n>>><\/span> b2<\/span>.<\/span>id<\/span>     # \u8fd4\u56deNone\uff0c\u56e0\u4e3a\u6b64\u65f6b2\u8fd8\u6ca1\u6709\u5199\u5165\u6570\u636e\u5e93\uff0c\u6ca1\u6709id\u503c<\/span>\r\n>>><\/span> b2<\/span>.<\/span>save<\/span>()<\/span>\r\n>>><\/span> b2<\/span>.<\/span>id<\/span>     # \u8fd9\u56de\u6709\u4e86<\/span>\r\n<\/pre>\n<\/div>\n
\u5f53\u7136\uff0c\u4f60\u4e5f\u53ef\u4ee5\u81ea\u5df1\u6307\u5b9a\u4e3b\u952e\u7684\u503c\uff0c\u4e0d\u9700\u8981\u7b49\u5f85\u6570\u636e\u5e93\u4e3a\u4e3b\u952e\u5206\u914d\u503c\uff0c\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n
\n
>>><\/span> b3<\/span> =<\/span> Blog<\/span>(<\/span>id<\/span>=<\/span>3<\/span>,<\/span> name<\/span>=<\/span>'Cheddar Talk'<\/span>,<\/span> tagline<\/span>=<\/span>'Thoughts on cheese.'<\/span>)<\/span>\r\n>>><\/span> b3<\/span>.<\/span>id<\/span>     # \u8fd4\u56de 3.<\/span>\r\n>>><\/span> b3<\/span>.<\/span>save<\/span>()<\/span>\r\n>>><\/span> b3<\/span>.<\/span>id<\/span>     # \u8fd4\u56de 3.<\/span>\r\n<\/pre>\n<\/div>\n
\u5f88\u663e\u7136\uff0c\u4f60\u5fc5\u987b\u786e\u4fdd\u5206\u914d\u7684\u4e3b\u952e\u503c\u662f\u6ca1\u6709\u88ab\u4f7f\u7528\u8fc7\u7684\uff0c\u5426\u5219\u80af\u5b9a\u51fa\u95ee\u9898\uff0c\u56e0\u4e3a\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0cDjango\u8ba4\u4e3a\u4f60\u662f\u5728\u66f4\u65b0\u4e00\u6761\u5df2\u6709\u7684\u6570\u636e\u5bf9\u8c61\uff0c\u800c\u4e0d\u662f\u65b0\u5efa\u5bf9\u8c61\uff0c\u6bd4\u5982\u4e0b\u9762\u7684\u64cd\u4f5c\uff1a<\/p>\n
\n
b4<\/span> =<\/span> Blog<\/span>(<\/span>id<\/span>=<\/span>3<\/span>,<\/span> name<\/span>=<\/span>'Not Cheddar'<\/span>,<\/span> tagline<\/span>=<\/span>'Anything but cheese.'<\/span>)<\/span>\r\nb4<\/span>.<\/span>save<\/span>()<\/span> \r\n# \u5b9e\u9645\u4e0a\u662f\u66f4\u65b0\u4e86\u4e0a\u9762\u7684b3\uff0c\u800c\u4e0d\u662f\u65b0\u5efa\uff0c\u6b64\u65f6b4==b3<\/span>\r\n<\/pre>\n<\/div>\n
\u4e0a\u9762\u73b0\u8c61\u7684\u672c\u8d28\u662fDjango\u5bf9SQL\u7684INSERT\u548cUPDATE\u8bed\u53e5\u8fdb\u884c\u4e86\u62bd\u8c61\u5408\u5e76\uff0c\u5171\u7528\u4e00\u4e2asave\u65b9\u6cd5\u3002<\/p>\n
\u6709\u4e9b\u7f55\u89c1\u60c5\u51b5\u4e0b\uff0c\u53ef\u80fd\u4f60\u5fc5\u987b\u5f3a\u5236\u8fdb\u884cINSERT\u6216\u8005UPDATE\u64cd\u4f5c\uff0c\u800c\u4e0d\u662f\u8ba9Django\u81ea\u52a8\u51b3\u5b9a\u3002\u8fd9\u65f6\u5019\u53ef\u4ee5\u4f7f\u7528save\u65b9\u6cd5\u7684force_insert<\/code>\u548cforce_update<\/code>\u53c2\u6570\uff0c\u5c06\u5176\u4e2d\u4e4b\u4e00\u8bbe\u7f6e\u4e3aTrue\uff0c\u5f3a\u5236\u6307\u5b9a\u4fdd\u5b58\u6a21\u5f0f\u3002<\/p>\n
\u53e6\u5916\uff0c\u6709\u4e00\u79cd\u5e38\u89c1\u7684\u9700\u6c42\u662f\u6839\u636e\u73b0\u6709\u5b57\u6bb5\u7684\u503c\uff0c\u66f4\u65b0\u6210\u4e3a\u65b0\u7684\u503c\uff0c\u6bd4\u5982\u70b9\u8d5e\u6570+1\u7684\u64cd\u4f5c\uff0c\u901a\u5e38\u6211\u4eec\u53ef\u80fd\u5199\u6210\u5982\u4e0b\u7684\u4ee3\u7801\uff1a<\/p>\n
\n
>>><\/span> entry<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>name<\/span>=<\/span>'\u5218\u6c5f\u7684\u535a\u5ba2'<\/span>)<\/span>\r\n>>><\/span> entry<\/span>.<\/span>number_of_pingbacks<\/span> +=<\/span> 1<\/span>\r\n>>><\/span> entry<\/span>.<\/span>save<\/span>()<\/span>\r\n<\/pre>\n<\/div>\n
\u770b\u8d77\u6765\u6ca1\u6709\u4ec0\u4e48\u95ee\u9898\uff0c\u4f46\u5b9e\u9645\u4e0a\u8fd9\u91cc\u6709\u4e2a\u6f0f\u6d1e\u3002\u9996\u5148\u4f1a\u8bbf\u95ee\u4e00\u6b21\u6570\u636e\u5e93\uff0c\u5c06number_of_pingbacks\u7684\u503c\u53d6\u51fa\u6765\uff0c\u7136\u540e\u5728Python\u7684\u5185\u5b58\u4e2d\u8fdb\u884c\u52a0\u4e00\u64cd\u4f5c\uff0c\u6700\u540e\u5c06\u65b0\u7684\u503c\u5199\u56de\u5230\u6570\u636e\u5e93\u3002\u4e24\u6b21\u8bfb\u5199\u5012\u8fd8\u7b97\u597d\uff0c\u5173\u952e\u662f\u53ef\u80fd\u5b58\u5728\u6570\u636e\u51b2\u7a81\uff0c\u6bd4\u5982\u5728\u540c\u4e00\u65f6\u95f4\u6709\u5f88\u591a\u4eba\u70b9\u8d5e\uff0c\u80af\u5b9a\u4f1a\u51fa\u73b0\u9519\u8bef\u3002\u90a3\u5982\u4f55\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\u5462\uff1f\u6700\u7b80\u5355\u7684\u65b9\u6cd5\u662f\u4f7f\u7528Django\u7684F\u8868\u8fbe\u5f0f<\/code>\uff1a<\/p>\n
\n
>>><\/span> from<\/span> django.db.models<\/span> import<\/span> F<\/span>\r\n\r\n>>><\/span> entry<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>name<\/span>=<\/span>'\u5218\u6c5f\u7684\u535a\u5ba2'<\/span>)<\/span>\r\n>>><\/span> entry<\/span>.<\/span>number_of_pingbacks<\/span> =<\/span> F<\/span>(<\/span>'number_of_pingbacks'<\/span>)<\/span> +<\/span> 1<\/span>\r\n>>><\/span> entry<\/span>.<\/span>save<\/span>()<\/span>\r\n<\/pre>\n<\/div>\n
\u4e3a\u4ec0\u4e48F\u8868\u8fbe\u5f0f\u5c31\u53ef\u4ee5\u907f\u514d\u4e0a\u9762\u7684\u95ee\u9898\u5462\uff1f\u56e0\u4e3aDjango\u8bbe\u8ba1\u7684\u8fd9\u4e2aF\u8868\u8fbe\u5f0f\u5728\u83b7\u53d6\u5173\u8054\u5b57\u6bb5\u503c\u7684\u65f6\u5019\u4e0d\u7528\u5148\u53bb\u6570\u636e\u5e93\u4e2d\u53d6\u503c\u7136\u540e\u5728Python\u5185\u5b58\u91cc\u8ba1\u7b97\uff0c\u800c\u662f\u76f4\u63a5\u5728\u6570\u636e\u5e93\u4e2d\u53d6\u503c\u548c\u8ba1\u7b97\uff0c\u76f4\u63a5\u66f4\u65b0\u6570\u636e\u5e93\uff0c\u4e0d\u9700\u8981\u5728Python\u4e2d\u64cd\u4f5c\uff0c\u81ea\u7136\u5c31\u4e0d\u5b58\u5728\u6570\u636e\u7ade\u4e89\u548c\u51b2\u7a81\u95ee\u9898\u4e86\u3002<\/p>\n
save\u65b9\u6cd5\u7684\u6700\u540e\u4e00\u4e2a\u53c2\u6570\u662fupdate_fields<\/code><\/span>\uff0c\u5b83\u7528\u4e8e\u6307\u5b9a\u4f60\u8981\u5bf9\u6a21\u578b\u7684\u54ea\u4e9b\u5b57\u6bb5\u8fdb\u884c\u66f4\u65b0\uff0c\u8fd9\u5bf9\u4e8e\u6027\u80fd\u53ef\u80fd\u6709\u7ec6\u5fae\u5730\u63d0\u5347\uff0c\u6bd4\u5982\uff1a<\/p>\n
\n
product<\/span>.<\/span>name<\/span> =<\/span> 'Name changed again'<\/span>\r\nproduct<\/span>.<\/span>save<\/span>(<\/span>update_fields<\/span>=<\/span>[<\/span>'name'<\/span>])<\/span>\r\n<\/pre>\n<\/div>\n
\u4e00\u4e9bupdate_fields<\/code>\u53c2\u6570\u7684\u8bf4\u660e\uff1a<\/p>\n
    \n
  • \u63a5\u6536\u4efb\u4f55\u7684\u53ef\u8fed\u4ee3\u5bf9\u8c61\uff0c\u6bcf\u4e2a\u5143\u7d20\u90fd\u662f\u5b57\u7b26\u4e32<\/li>\n
  • \u53c2\u6570\u503c\u4e3a\u7a7a\u7684\u8fed\u4ee3\u5bf9\u8c61\u65f6\uff0c\u76f8\u5f53\u4e8e\u8df3\u8fc7save\u65b9\u6cd5<\/li>\n
  • \u53c2\u6570\u503c\u4e3aNone\u65f6\uff0c\u9ed8\u8ba4\u66f4\u65b0\u6240\u6709\u5b57\u6bb5<\/li>\n
  • \u5c06\u5f3a\u5236\u4e3aUPDATE\u65b9\u5f0f<\/li>\n<\/ul>\n
    \u90a3\u4e48\u5f53\u4f60\u8c03\u7528save()\u65b9\u6cd5\u7684\u65f6\u5019\uff0cDjango\u5185\u90e8\u662f\u600e\u4e48\u7684\u6267\u884c\u987a\u5e8f\u5462\uff1f<\/p>\n
      \n
    1. \u89e6\u53d1pre-save<\/code><\/span>\u4fe1\u53f7\uff0c\u8ba9\u4efb\u4f55\u76d1\u542c\u6b64\u4fe1\u53f7\u8005\u6267\u884c\u52a8\u4f5c<\/li>\n
    2. \u9884\u5904\u7406\u6570\u636e\u3002\u89e6\u53d1\u6bcf\u4e2a\u5b57\u6bb5\u7684pre-save()<\/code><\/span>\u65b9\u6cd5\uff0c\u7528\u4e8e\u5b9e\u65bd\u81ea\u52a8\u5730\u6570\u636e\u4fee\u6539\u52a8\u4f5c\uff0c\u6bd4\u5982\u65f6\u95f4\u5b57\u6bb5\u5904\u7406auto_now_add<\/code>\u6216\u8005auto_now<\/code>\u53c2\u6570\u3002<\/li>\n
    3. \u51c6\u5907\u6570\u636e\u5e93\u6570\u636e\u3002<\/span>\u00a0\u8981\u6c42\u6bcf\u4e2a\u5b57\u6bb5\u63d0\u4f9b\u7684\u5f53\u524d\u503c\u662f\u80fd\u591f\u5199\u5165\u5230\u6570\u636e\u5e93\u4e2d\u7684\u7c7b\u578b\u3002\u7c7b\u4f3c\u6574\u6570\u3001\u5b57\u7b26\u4e32\u7b49\u5927\u591a\u6570\u7c7b\u578b\u4e0d\u9700\u8981\u5904\u7406\uff0c\u53ea\u6709\u4e00\u4e9b\u590d\u6742\u7684\u7c7b\u578b\u9700\u8981\u505a\u8f6c\u6362\uff0c\u6bd4\u5982\u65f6\u95f4\u3002<\/li>\n
    4. \u5c06\u6570\u636e\u63d2\u5165\u5230\u6570\u636e\u5e93\u5185\u3002<\/li>\n
    5. \u89e6\u53d1post_save<\/code>\u4fe1\u53f7\u3002<\/li>\n<\/ol>\n
      \u6ce8\u610f\uff1a\u5bf9\u4e8e\u6279\u91cf\u521b\u5efa\u548c\u6279\u91cf\u66f4\u65b0\u64cd\u4f5c\uff0csave()\u65b9\u6cd5\u4e0d\u4f1a\u8c03\u7528\uff0c\u751a\u81f3\u8fdepre_delete<\/code>\u6216\u8005post_delete<\/code>\u4fe1\u53f7\u90fd\u4e0d\u4f1a\u89e6\u53d1\uff0c\u6b64\u65f6\u81ea\u5b9a\u4e49\u7684\u4ee3\u7801\u90fd\u662f\u65e0\u6548\u7684\u3002<\/p>\n
      \u4fdd\u5b58\u5916\u952e\u548c\u591a\u5bf9\u591a\u5b57\u6bb5<\/span>:<\/p>\n
      \u4fdd\u5b58\u4e00\u4e2a\u5916\u952e\u5b57\u6bb5\u548c\u4fdd\u5b58\u666e\u901a\u5b57\u6bb5\u6ca1\u4ec0\u4e48\u533a\u522b\uff0c\u53ea\u662f\u8981\u6ce8\u610f\u503c\u7684\u7c7b\u578b\u8981\u6b63\u786e\u3002\u4e0b\u9762\u7684\u4f8b\u5b50\uff0c\u6709\u4e00\u4e2aEntry\u7684\u5b9e\u4f8bentry\u548c\u4e00\u4e2aBlog\u7684\u5b9e\u4f8bcheese_blog<\/code>\uff0c\u7136\u540e\u628acheese_blog<\/code>\u4f5c\u4e3a\u503c\u8d4b\u7ed9\u4e86entry\u7684blog\u5c5e\u6027\uff0c\u6700\u540e\u8c03\u7528save\u65b9\u6cd5\u8fdb\u884c\u4fdd\u5b58\u3002<\/p>\n
      \n
      >>><\/span> from<\/span> blog.models<\/span> import<\/span> Blog<\/span>,<\/span> Entry<\/span>\r\n>>><\/span> entry<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>pk<\/span>=<\/span>1<\/span>)<\/span>\r\n>>><\/span> cheese_blog<\/span> =<\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>name<\/span>=<\/span>\"Cheddar Talk\"<\/span>)<\/span>\r\n>>><\/span> entry<\/span>.<\/span>blog<\/span> =<\/span> cheese_blog<\/span>\r\n>>><\/span> entry<\/span>.<\/span>save<\/span>()<\/span>\r\n<\/pre>\n<\/div>\n
      \u591a\u5bf9\u591a\u5b57\u6bb5\u7684\u4fdd\u5b58\u7a0d\u5fae\u6709\u70b9\u533a\u522b\uff0c\u9700\u8981\u8c03\u7528\u4e00\u4e2aadd()<\/code>\u65b9\u6cd5\uff0c\u800c\u4e0d\u662f\u76f4\u63a5\u7ed9\u5c5e\u6027\u8d4b\u503c\uff0c\u4f46\u5b83\u4e0d\u9700\u8981\u8c03\u7528save\u65b9\u6cd5\u3002\u5982\u4e0b\u4f8b\u6240\u793a\uff1a<\/p>\n
      \n
      >>><\/span> from<\/span> blog.models<\/span> import<\/span> Author<\/span>\r\n>>><\/span> joe<\/span> =<\/span> Author<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>\"Joe\"<\/span>)<\/span>\r\n>>><\/span> entry<\/span>.<\/span>authors<\/span>.<\/span>add<\/span>(<\/span>joe<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
      \u5728\u4e00\u884c\u8bed\u53e5\u5185\uff0c\u53ef\u4ee5\u540c\u65f6\u6dfb\u52a0\u591a\u4e2a\u5bf9\u8c61\u5230\u591a\u5bf9\u591a\u7684\u5b57\u6bb5\uff0c\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n
      \n
      >>><\/span> john<\/span> =<\/span> Author<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>\"John\"<\/span>)<\/span>\r\n>>><\/span> paul<\/span> =<\/span> Author<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>\"Paul\"<\/span>)<\/span>\r\n>>><\/span> george<\/span> =<\/span> Author<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>\"George\"<\/span>)<\/span>\r\n>>><\/span> ringo<\/span> =<\/span> Author<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>\"Ringo\"<\/span>)<\/span>\r\n>>><\/span> entry<\/span>.<\/span>authors<\/span>.<\/span>add<\/span>(<\/span>john<\/span>,<\/span> paul<\/span>,<\/span> george<\/span>,<\/span> ringo<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
      \u5982\u679c\u4f60\u6307\u5b9a\u6216\u6dfb\u52a0\u4e86\u9519\u8bef\u7c7b\u578b\u7684\u5bf9\u8c61\uff0cDjango\u4f1a\u629b\u51fa\u5f02\u5e38\u3002<\/p>\n
      \u4e09\u3001\u68c0\u7d22\u5bf9\u8c61<\/h1>\n
      \u60f3\u8981\u4ece\u6570\u636e\u5e93\u5185\u68c0\u7d22\u5bf9\u8c61\uff0c\u4f60\u9700\u8981\u57fa\u4e8e\u6a21\u578b\u7c7b\uff0c\u901a\u8fc7\u7ba1\u7406\u5668\uff08Manager\uff09\u64cd\u4f5c\u6570\u636e\u5e93\u5e76\u8fd4\u56de\u4e00\u4e2a\u67e5\u8be2\u7ed3\u679c\u96c6\uff08QuerySet\uff09\u3002<\/p>\n
      \u6bcf\u4e2aQuerySet\u4ee3\u8868\u4e00\u4e9b\u6570\u636e\u5e93\u5bf9\u8c61\u7684\u96c6\u5408\u3002\u5b83\u53ef\u4ee5\u5305\u542b\u96f6\u4e2a\u3001\u4e00\u4e2a\u6216\u591a\u4e2a\u8fc7\u6ee4\u5668\uff08filters\uff09\u3002Filters\u7f29\u5c0f\u67e5\u8be2\u7ed3\u679c\u7684\u8303\u56f4\u3002\u5728SQL\u8bed\u6cd5\u4e2d\uff0c\u4e00\u4e2aQuerySet\u76f8\u5f53\u4e8e\u4e00\u4e2aSELECT\u8bed\u53e5\uff0c\u800cfilter\u5219\u76f8\u5f53\u4e8eWHERE\u6216\u8005LIMIT\u4e00\u7c7b\u7684\u5b50\u53e5\u3002<\/p>\n
      \u6bcf\u4e2a\u6a21\u578b\u81f3\u5c11\u5177\u6709\u4e00\u4e2aManager\uff0c\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0cDjango\u81ea\u52a8\u4e3a\u6211\u4eec\u63d0\u4f9b\u4e86\u4e00\u4e2a\uff0c\u4e5f\u662f\u6700\u5e38\u7528\u6700\u91cd\u8981\u7684\u4e00\u4e2a\uff0c99%\u7684\u60c5\u51b5\u4e0b\u6211\u4eec\u90fd\u53ea\u4f7f\u7528\u5b83\u3002\u5b83\u88ab\u79f0\u4f5cobjects<\/code>\uff0c\u53ef\u4ee5\u901a\u8fc7\u6a21\u578b\u7c7b\u76f4\u63a5\u8c03\u7528\u5b83\uff0c\u4f46\u4e0d\u80fd\u901a\u8fc7\u6a21\u578b\u7c7b\u7684\u5b9e\u4f8b\u8c03\u7528\u5b83\uff0c\u4ee5\u6b64\u5b9e\u73b0\u201c\u8868\u7ea7\u522b\u201d\u64cd\u4f5c\u548c\u201c\u8bb0\u5f55\u7ea7\u522b\u201d\u64cd\u4f5c\u7684\u5f3a\u5236\u5206\u79bb\u3002<\/p>\n
      \u9ed8\u8ba4\u7684objects<\/code>\u7ba1\u7406\u5668\u5e26\u6709\u4e00\u7cfb\u5217\u65b9\u6cd5\u548c\u5c5e\u6027\uff0c\u80fd\u591f\u6ee1\u8db3\u7edd\u5927\u591a\u6570\u573a\u666f\u7684\u4e1a\u52a1\u9700\u6c42\u3002<\/p>\n
      \n
      >>><\/span> Blog<\/span>.<\/span>objects<\/span>\r\n<<\/span>django<\/span>.<\/span>db<\/span>.<\/span>models<\/span>.<\/span>manager<\/span>.<\/span>Manager<\/span> object<\/span> at<\/span> ...><\/span>\r\n>>><\/span> b<\/span> =<\/span> Blog<\/span>(<\/span>name<\/span>=<\/span>'Foo'<\/span>,<\/span> tagline<\/span>=<\/span>'Bar'<\/span>)<\/span>\r\n>>><\/span> b<\/span>.<\/span>objects<\/span>\r\nTraceback<\/span>:<\/span>\r\n...<\/span>\r\nAttributeError<\/span>:<\/span> \"Manager isn't accessible via Blog instances.\"<\/span>\r\n<\/pre>\n<\/div>\n
      \u5728\u6784\u9020\u81ea\u5df1\u7684\u68c0\u7d22\u8bed\u53e5\u4e4b\u524d\uff0c\u8bf7\u8bb0\u4f4f\uff1a\u5e0c\u671b\u7ed3\u679c\u662f\u54ea\u4e2a\u6a21\u578b\u7684\u5b9e\u4f8b\uff0c\u5c31\u7528\u54ea\u4e2a\u6a21\u578b\u53bb\u8c03\u7528\uff01<\/code>\u3002\u6bd4\u5982\uff0c\u6211\u60f3\u83b7\u5f97\u6ee1\u8db3\u67d0\u4e9b\u6761\u4ef6\u7684Blog\uff0c\u90a3\u4e48\u5c31\u662fBlog.objects.xxx<\/code>\uff0c\u5982\u679c\u60f3\u83b7\u5f97\u67d0\u4e9bEntry\uff0c\u90a3\u4e48\u5c31\u662fEntry.objects.xxx<\/code>\u3002<\/span><\/p>\n
      1. \u68c0\u7d22\u6240\u6709\u5bf9\u8c61<\/h2>\n
      \u4f7f\u7528all()<\/code>\u65b9\u6cd5\uff0c\u53ef\u4ee5\u83b7\u53d6\u67d0\u5f20\u8868\u7684\u6240\u6709\u8bb0\u5f55\u3002<\/p>\n
      \n
      >>> all_entries = Entry.objects.all()\r\n<\/pre>\n<\/div>\n
      2. \u8fc7\u6ee4\u5bf9\u8c61<\/h2>\n
      \u6709\u4e24\u79cd\u65b9\u6cd5\u53ef\u4ee5\u7528\u6765\u8fc7\u6ee4QuerySet\u7684\u7ed3\u679c\uff0c\u5206\u522b\u662f\uff1a<\/p>\n
        \n
      • filter(**kwargs)<\/code>\uff1a\u8fd4\u56de\u4e00\u4e2a\u6839\u636e\u6307\u5b9a\u53c2\u6570\u67e5\u8be2\u51fa\u6765\u7684QuerySet<\/li>\n
      • exclude(**kwargs)<\/code>\uff1a\u8fd4\u56de\u9664\u4e86\u6839\u636e\u6307\u5b9a\u53c2\u6570\u67e5\u8be2\u51fa\u6765\u7ed3\u679c\u7684QuerySet<\/li>\n<\/ul>\n
        \u5176\u4e2d\uff0c**kwargs<\/code>\u53c2\u6570\u7684\u683c\u5f0f\u5fc5\u987b\u662fDjango\u8bbe\u7f6e\u7684\u4e00\u4e9b\u5b57\u6bb5\u683c\u5f0f\u3002<\/p>\n
        \u4f8b\u5982\u8981\u83b7\u53d62020\u5e74\u7684\u6240\u6709\u6587\u7ae0\uff1a<\/p>\n
        \n
        Entry.objects.filter(pub_date__year=2020)\r\n<\/pre>\n<\/div>\n
        \u5b83\u7b49\u540c\u4e8e\uff1a<\/p>\n
        \n
        Entry.objects.all().filter(pub_date__year=2020)\r\n<\/pre>\n<\/div>\n
        \u94fe\u5f0f\u8fc7\u6ee4<\/span><\/p>\n
        filter\u548cexclude\u7684\u7ed3\u679c\u4f9d\u7136\u662f\u4e2aQuerySet\uff0c\u56e0\u6b64\u5b83\u53ef\u4ee5\u7ee7\u7eed\u88abfilter\u548cexclude\uff0c\u8fd9\u5c31\u5f62\u6210\u4e86\u94fe\u5f0f\u8fc7\u6ee4\uff1a<\/p>\n
        \n
        >>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>\r\n...<\/span>     headline__startswith<\/span>=<\/span>'What'<\/span>\r\n...<\/span> )<\/span>.<\/span>exclude<\/span>(<\/span>\r\n...<\/span>     pub_date__gte<\/span>=<\/span>datetime<\/span>.<\/span>date<\/span>.<\/span>today<\/span>()<\/span>\r\n...<\/span> )<\/span>.<\/span>filter<\/span>(<\/span>\r\n...<\/span>     pub_date__gte<\/span>=<\/span>datetime<\/span>(<\/span>2020<\/span>,<\/span> 1<\/span>,<\/span> 30<\/span>)<\/span>\r\n...<\/span> )<\/span>\r\n<\/pre>\n<\/div>\n
        \u6700\u7ec8\u7684\u00a0QuerySet<\/code>\u00a0\u5305\u542b\u6807\u9898\u4ee5 “What” \u5f00\u5934\u7684\uff0c\u53d1\u5e03\u65e5\u671f\u4ecb\u4e8e 2020 \u5e74 1 \u6708 30 \u65e5\u4e0e\u4eca\u5929\u4e4b\u95f4\u7684\u6240\u6709\u6761\u76ee\u3002<\/p>\n
        \uff08\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u5f53\u5728\u8fdb\u884c\u8de8\u5173\u7cfb\u7684\u94fe\u5f0f\u8fc7\u6ee4\u65f6\uff0c\u7ed3\u679c\u53ef\u80fd\u548c\u4f60\u60f3\u8c61\u7684\u4e0d\u4e00\u6837\uff0c\u53c2\u8003\u4e0b\u9762\u7684\u8de8\u591a\u503c\u5173\u7cfb\u67e5\u8be2\uff09<\/p>\n
        \u88ab\u8fc7\u6ee4\u7684QuerySets\u90fd\u662f\u552f\u4e00\u7684<\/span><\/p>\n
        \u6bcf\u4e00\u6b21\u8fc7\u6ee4\uff0c\u4f60\u90fd\u4f1a\u83b7\u5f97\u4e00\u4e2a\u5168\u65b0\u7684QuerySet\uff0c\u5b83\u548c\u4e4b\u524d\u7684QuerySet\u6ca1\u6709\u4efb\u4f55\u5173\u7cfb\uff0c\u53ef\u4ee5\u5b8c\u5168\u72ec\u7acb\u7684\u88ab\u4fdd\u5b58\uff0c\u4f7f\u7528\u548c\u91cd\u7528\u3002\u4f8b\u5982\uff1a<\/p>\n
        \n
        >>><\/span> q1<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>headline__startswith<\/span>=<\/span>\"What\"<\/span>)<\/span>\r\n>>><\/span> q2<\/span> =<\/span> q1<\/span>.<\/span>exclude<\/span>(<\/span>pub_date__gte<\/span>=<\/span>datetime<\/span>.<\/span>date<\/span>.<\/span>today<\/span>())<\/span>\r\n>>><\/span> q3<\/span> =<\/span> q1<\/span>.<\/span>filter<\/span>(<\/span>pub_date__gte<\/span>=<\/span>datetime<\/span>.<\/span>date<\/span>.<\/span>today<\/span>())<\/span>\r\n<\/pre>\n<\/div>\n
        \u8fd9\u4e09\u4e2a QuerySets \u662f\u72ec\u7acb\u7684\u3002\u7b2c\u4e00\u4e2a\u662f\u57fa\u7840 QuerySet\uff0c\u5305\u542b\u4e86\u6240\u6709\u6807\u9898\u4ee5 “What” \u5f00\u5934\u7684\u6587\u7ae0\u3002\u7b2c\u4e8c\u4e2a\u662f\u7b2c\u4e00\u4e2a\u7684\u5b50\u96c6\uff0c\u5e26\u6709\u989d\u5916\u6761\u4ef6\uff0c\u6392\u9664\u4e86 pub_date \u662f\u4eca\u5929\u548c\u4eca\u5929\u4e4b\u540e\u7684\u6240\u6709\u8bb0\u5f55\u3002\u7b2c\u4e09\u4e2a\u662f\u7b2c\u4e00\u4e2a\u7684\u5b50\u96c6\uff0c\u5e26\u6709\u989d\u5916\u6761\u4ef6\uff0c\u53ea\u7b5b\u9009 pub_date \u662f\u4eca\u5929\u6216\u672a\u6765\u7684\u6240\u6709\u8bb0\u5f55\u3002\u6700\u521d\u7684 QuerySet (q1) \u4e0d\u53d7\u7b5b\u9009\u64cd\u4f5c\u5f71\u54cd\u3002<\/p>\n
        QuerySets\u90fd\u662f\u61d2\u60f0\u7684<\/span><\/p>\n
        \u4e00\u4e2a\u521b\u5efaQuerySets\u7684\u52a8\u4f5c\u4e0d\u4f1a\u7acb\u523b\u5bfc\u81f4\u4efb\u4f55\u7684\u6570\u636e\u5e93\u884c\u4e3a\u3002\u4f60\u53ef\u4ee5\u4e0d\u65ad\u5730\u8fdb\u884cfilter\u52a8\u4f5c\u4e00\u6574\u5929\uff0cDjango\u4e0d\u4f1a\u8fd0\u884c\u4efb\u4f55\u5b9e\u9645\u7684\u6570\u636e\u5e93\u67e5\u8be2\u52a8\u4f5c\uff0c\u76f4\u5230QuerySets\u88ab\u63d0\u4ea4(evaluated)\u3002<\/p>\n
        \u7b80\u800c\u8a00\u4e4b\u5c31\u662f\uff0c\u53ea\u6709\u78b0\u5230\u67d0\u4e9b\u7279\u5b9a\u7684\u64cd\u4f5c\uff0cDjango\u624d\u4f1a\u5c06\u6240\u6709\u7684\u64cd\u4f5c\u4f53\u73b0\u5230\u6570\u636e\u5e93\u5185\uff0c\u5426\u5219\u5b83\u4eec\u53ea\u662f\u4fdd\u5b58\u5728\u5185\u5b58\u548cDjango\u7684\u5c42\u9762\u4e2d\u3002\u8fd9\u662f\u4e00\u79cd\u63d0\u9ad8\u6570\u636e\u5e93\u67e5\u8be2\u6548\u7387\uff0c\u51cf\u5c11\u64cd\u4f5c\u6b21\u6570\u7684\u4f18\u5316\u8bbe\u8ba1\u3002\u770b\u4e0b\u9762\u7684\u4f8b\u5b50\uff1a<\/p>\n
        \n
        >>><\/span> q<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>headline__startswith<\/span>=<\/span>\"What\"<\/span>)<\/span>\r\n>>><\/span> q<\/span> =<\/span> q<\/span>.<\/span>filter<\/span>(<\/span>pub_date__lte<\/span>=<\/span>datetime<\/span>.<\/span>date<\/span>.<\/span>today<\/span>())<\/span>\r\n>>><\/span> q<\/span> =<\/span> q<\/span>.<\/span>exclude<\/span>(<\/span>body_text__icontains<\/span>=<\/span>\"food\"<\/span>)<\/span>\r\n>>><\/span> print<\/span>(<\/span>q<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
        \u4e0a\u9762\u7684\u4f8b\u5b50\uff0c\u770b\u8d77\u6765\u6267\u884c\u4e863\u6b21\u6570\u636e\u5e93\u8bbf\u95ee\uff0c\u5b9e\u9645\u4e0a\u53ea\u662f\u5728print\u8bed\u53e5\u65f6\u624d\u6267\u884c1\u6b21\u8bbf\u95ee\u3002\u901a\u5e38\u60c5\u51b5\uff0cQuerySets\u7684\u68c0\u7d22\u4e0d\u4f1a\u7acb\u523b\u6267\u884c\u5b9e\u9645\u7684\u6570\u636e\u5e93\u67e5\u8be2\u64cd\u4f5c\uff0c\u76f4\u5230\u51fa\u73b0\u7c7b\u4f3cprint\u7684\u8bf7\u6c42\uff0c\u4e5f\u5c31\u662f\u6240\u8c13\u7684evaluated\u3002<\/p>\n
        \u90a3\u4e48\u5982\u4f55\u5224\u65ad\u54ea\u79cd\u64cd\u4f5c\u4f1a\u89e6\u53d1\u771f\u6b63\u7684\u6570\u636e\u5e93\u64cd\u4f5c\u5462\uff1f\u7b80\u5355\u7684\u903b\u8f91\u601d\u7ef4\u5982\u4e0b\uff1a<\/p>\n
          \n
        • \u7b2c\u4e00\u6b21\u9700\u8981\u771f\u6b63\u64cd\u4f5c\u6570\u636e\u7684\u503c\u7684\u65f6\u5019\u3002\u6bd4\u5982\u4e0a\u9762print(q)\uff0c\u5982\u679c\u4f60\u4e0d\u53bb\u6570\u636e\u5e93\u62ffq\uff0cprint\u4ec0\u4e48\u5462\uff1f<\/li>\n
        • \u843d\u5b9e\u4fee\u6539\u52a8\u4f5c\u7684\u65f6\u5019\u3002\u4f60\u4e0d\u64cd\u4f5c\u6570\u636e\u5e93\uff0c\u600e\u4e48\u843d\u5b9e\uff1f<\/li>\n<\/ul>\n
          3. \u68c0\u7d22\u5355\u4e00\u5bf9\u8c61<\/h2>\n
          filter\u65b9\u6cd5\u59cb\u7ec8\u8fd4\u56de\u7684\u662fQuerySets\uff0c\u90a3\u6015\u53ea\u6709\u4e00\u4e2a\u5bf9\u8c61\u7b26\u5408\u8fc7\u6ee4\u6761\u4ef6\uff0c\u8fd4\u56de\u7684\u4e5f\u662f\u5305\u542b\u4e00\u4e2a\u5bf9\u8c61\u7684QuerySets\uff0c\u8fd9\u662f\u4e00\u4e2a\u96c6\u5408\u7c7b\u578b\u5bf9\u8c61\uff0c\u4f60\u53ef\u4ee5\u7c7b\u6bd4Python\u5217\u8868\uff0c\u53ef\u8fed\u4ee3\u53ef\u5faa\u73af\u53ef\u7d22\u5f15\u3002<\/p>\n
          \u5982\u679c\u4f60\u786e\u5b9a\u4f60\u7684\u68c0\u7d22\u53ea\u4f1a\u83b7\u5f97\u4e00\u4e2a\u5bf9\u8c61\uff0c\u90a3\u4e48\u4f60\u53ef\u4ee5\u4f7f\u7528Manager\u7684get()\u65b9\u6cd5\u6765\u76f4\u63a5\u8fd4\u56de\u8fd9\u4e2a\u5bf9\u8c61\u3002<\/p>\n
          \n
          >>> one_entry = Entry.objects.get(pk=1)\r\n<\/pre>\n<\/div>\n
          \u5728get\u65b9\u6cd5\u4e2d\u4f60\u53ef\u4ee5\u4f7f\u7528\u4efb\u4f55filter\u65b9\u6cd5\u4e2d\u7684\u67e5\u8be2\u53c2\u6570\uff0c\u7528\u6cd5\u4e5f\u662f\u4e00\u6a21\u4e00\u6837\u3002<\/p>\n
          \u6ce8\u610f<\/span>\uff1a\u4f7f\u7528get()\u65b9\u6cd5\u548c\u4f7f\u7528filter()\u65b9\u6cd5\u7136\u540e\u901a\u8fc7[0]\u7684\u65b9\u5f0f\u5206\u7247\uff0c\u6709\u7740\u4e0d\u540c\u7684\u5730\u65b9\u3002\u770b\u4f3c\u4e24\u8005\u90fd\u662f\u83b7\u53d6\u5355\u4e00\u5bf9\u8c61\u3002\u4f46\u662f\uff0c\u5982\u679c\u5728\u67e5\u8be2\u65f6\u6ca1\u6709\u5339\u914d\u5230\u5bf9\u8c61\uff0c\u90a3\u4e48get()\u65b9\u6cd5\u5c06\u629b\u51faDoesNotExist\u5f02\u5e38<\/span>\u3002\u8fd9\u4e2a\u5f02\u5e38\u662f\u6a21\u578b\u7c7b\u7684\u4e00\u4e2a\u5c5e\u6027\uff0c\u5728\u4e0a\u9762\u7684\u4f8b\u5b50\u4e2d\uff0c\u5982\u679c\u4e0d\u5b58\u5728\u4e3b\u952e\u4e3a1\u7684Entry\u5bf9\u8c61\uff0c\u90a3\u4e48Django\u5c06\u629b\u51faEntry.DoesNotExist<\/code>\u5f02\u5e38\u3002<\/p>\n
          \u7c7b\u4f3c\u5730\uff0c\u5728\u4f7f\u7528get()\u65b9\u6cd5\u67e5\u8be2\u65f6\uff0c\u5982\u679c\u7ed3\u679c\u8d85\u8fc71\u4e2a\uff0c\u5219\u4f1a\u629b\u51faMultipleObjectsReturned\u5f02\u5e38<\/span>\uff0c\u8fd9\u4e2a\u5f02\u5e38\u4e5f\u662f\u6a21\u578b\u7c7b\u7684\u4e00\u4e2a\u5c5e\u6027\u3002<\/p>\n
          \u6240\u4ee5\uff1aget()\u65b9\u6cd5\u8981\u614e\u7528\uff01<\/span><\/p>\n
          4. \u5176\u5b83QuerySet\u65b9\u6cd5<\/h2>\n
          \u5927\u591a\u6570\u60c5\u51b5\u4e0b\uff0c\u9700\u8981\u4ece\u6570\u636e\u5e93\u4e2d\u67e5\u627e\u5bf9\u8c61\u65f6\uff0c\u4f7f\u7528all()\u3001 get()\u3001filter() \u548cexclude()\u5c31\u884c\u3002\u9488\u5bf9QuerySet\u7684\u65b9\u6cd5\u8fd8\u6709\u5f88\u591a\uff0c\u90fd\u662f\u4e00\u4e9b\u76f8\u5bf9\u9ad8\u7ea7\u7684\u7528\u6cd5\u3002<\/p>\n
          5. QuerySet\u7684\u5207\u7247<\/h2>\n
          \u4f7f\u7528\u7c7b\u4f3cPython\u5bf9\u5217\u8868\u8fdb\u884c\u5207\u7247\u7684\u65b9\u6cd5\u53ef\u4ee5\u5bf9QuerySet\u8fdb\u884c\u8303\u56f4\u53d6\u503c\u3002\u5b83\u76f8\u5f53\u4e8eSQL\u8bed\u53e5\u4e2d\u7684LIMIT\u548cOFFSET\u5b50\u53e5\u3002\u53c2\u8003\u4e0b\u9762\u7684\u4f8b\u5b50\uff1a<\/p>\n
          \n
          >>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>all<\/span>()[:<\/span>5<\/span>]<\/span>      # \u8fd4\u56de\u524d5\u4e2a\u5bf9\u8c61<\/span>\r\n>>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>all<\/span>()[<\/span>5<\/span>:<\/span>10<\/span>]<\/span>    # \u8fd4\u56de\u7b2c6\u4e2a\u5230\u7b2c10\u4e2a\u5bf9\u8c61<\/span>\r\n<\/pre>\n<\/div>\n
          \u6ce8\u610f\uff1a\u4e0d\u652f\u6301\u8d1f\u7d22\u5f15\uff01\u4f8b\u5982 Entry.objects.all()[-1]\u662f\u4e0d\u5141\u8bb8\u7684<\/span><\/p>\n
          \u901a\u5e38\u60c5\u51b5\uff0c\u5207\u7247\u64cd\u4f5c\u4f1a\u8fd4\u56de\u4e00\u4e2a\u65b0\u7684QuerySet\uff0c\u5e76\u4e14\u4e0d\u4f1a\u88ab\u7acb\u523b\u6267\u884c\u3002\u4f46\u662f\u6709\u4e00\u4e2a\u4f8b\u5916\uff0c\u90a3\u5c31\u662f\u6307\u5b9a\u6b65\u957f\u7684\u65f6\u5019\uff0c\u67e5\u8be2\u64cd\u4f5c\u4f1a\u7acb\u523b\u5728\u6570\u636e\u5e93\u5185\u6267\u884c\uff0c\u5982\u4e0b\uff1a<\/p>\n
          \n
          >>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>all<\/span>()[:<\/span>10<\/span>:<\/span>2<\/span>]<\/span>\r\n<\/pre>\n<\/div>\n
          \u6ce8\u610f\uff1a\u7531\u4e8e queryset \u5207\u7247\u5de5\u4f5c\u65b9\u5f0f\u7684\u6a21\u7cca\u6027\uff0c\u7981\u6b62\u5bf9\u5176\u8fdb\u884c\u8fdb\u4e00\u6b65\u7684\u6392\u5e8f\u6216\u8fc7\u6ee4\u3002<\/p>\n
          \u82e5\u8981\u83b7\u53d6\u5355\u4e00\u7684\u5bf9\u8c61\u800c\u4e0d\u662f\u4e00\u4e2a\u5217\u8868\uff08\u4f8b\u5982\uff0cSELECT foo FROM bar LIMIT 1\uff09\uff0c\u53ef\u4ee5\u7b80\u5355\u5730\u4f7f\u7528\u7d22\u5f15\u800c\u4e0d\u662f\u5207\u7247\u3002\u4f8b\u5982\uff0c\u4e0b\u9762\u7684\u8bed\u53e5\u8fd4\u56de\u6570\u636e\u5e93\u4e2d\u6839\u636e\u6807\u9898\u6392\u5e8f\u540e\u7684\u7b2c\u4e00\u6761Entry\uff1a<\/p>\n
          \n
          >>> Entry.objects.order_by('headline')[0]\r\n<\/pre>\n<\/div>\n
          \u5b83\u76f8\u5f53\u4e8e\uff1a<\/p>\n
          \n
          >>> Entry.objects.order_by('headline')[0:1].get()\r\n<\/pre>\n<\/div>\n
          \u6ce8\u610f\uff1a\u5982\u679c\u6ca1\u6709\u5339\u914d\u5230\u5bf9\u8c61\uff0c\u90a3\u4e48\u7b2c\u4e00\u79cd\u65b9\u6cd5\u4f1a\u629b\u51faIndexError\u5f02\u5e38\uff0c\u800c\u7b2c\u4e8c\u79cd\u65b9\u5f0f\u4f1a\u629b\u51faDoesNotExist\u5f02\u5e38\u3002<\/p>\n
          \u4e5f\u5c31\u662f\u8bf4\u5728\u4f7f\u7528get\u548c\u5207\u7247\u7684\u65f6\u5019\uff0c\u8981\u6ce8\u610f\u67e5\u8be2\u7ed3\u679c\u7684\u5143\u7d20\u4e2a\u6570\u3002<\/p>\n
          6. \u5b57\u6bb5\u67e5\u8be2<\/h2>\n
          \u5b57\u6bb5\u67e5\u8be2\u662f\u6307\u5982\u4f55\u6307\u5b9aSQL WHERE\u5b50\u53e5\u7684\u5185\u5bb9\u3002\u5b83\u4eec\u7528\u4f5cQuerySet\u7684filter(), exclude()\u548cget()\u65b9\u6cd5\u7684\u5173\u952e\u5b57\u53c2\u6570\u3002<\/p>\n
          \u5176\u57fa\u672c\u683c\u5f0f\u662f\uff1afield__lookuptype=value<\/code>\uff0c\u6ce8\u610f\u5176\u4e2d\u662f\u53cc\u4e0b\u5212\u7ebf<\/span>\u3002<\/p>\n
          \u9ed8\u8ba4\u67e5\u627e\u7c7b\u578b\u4e3aexact\u3002<\/span><\/p>\n
          \u4f8b\u5982\uff1a<\/p>\n
          \n
          >>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>pub_date__lte<\/span>=<\/span>'2020-01-01'<\/span>)<\/span>\r\n#\u3000\u76f8\u5f53\u4e8e\uff1a<\/span>\r\nSELECT<\/span> *<\/span> FROM<\/span> blog_entry<\/span> WHERE<\/span> pub_date<\/span> <=<\/span> '2020-01-01'<\/span>;<\/span>\r\n<\/pre>\n<\/div>\n
          \u5176\u4e2d\u7684\u5b57\u6bb5\u5fc5\u987b\u662f\u6a21\u578b\u4e2d\u5b9a\u4e49\u7684\u5b57\u6bb5\u4e4b\u4e00\u3002\u4f46\u662f\u6709\u4e00\u4e2a\u4f8b\u5916\uff0c\u90a3\u5c31\u662fForeignKey\u5b57\u6bb5\uff0c\u4f60\u53ef\u4ee5\u4e3a\u5176\u6dfb\u52a0\u4e00\u4e2a_id<\/code>\u540e\u7f00\uff08\u5355\u4e0b\u5212\u7ebf\uff09\u3002\u8fd9\u79cd\u60c5\u51b5\u4e0b\u952e\u503c\u662f\u5916\u952e\u6a21\u578b\u7684\u4e3b\u952e\u539f\u751f\u503c\u3002\u4f8b\u5982\uff1a<\/p>\n
          \n
          >>> Entry.objects.filter(blog_id=4)\r\n<\/pre>\n<\/div>\n
          \u5982\u679c\u4f60\u4f20\u9012\u4e86\u4e00\u4e2a\u975e\u6cd5\u7684\u952e\u503c\uff0c\u67e5\u8be2\u51fd\u6570\u4f1a\u629b\u51faTypeError\u5f02\u5e38\u3002<\/p>\n
          Django\u7684\u6570\u636e\u5e93API\u652f\u630120\u591a\u79cd\u67e5\u8be2\u7c7b\u578b\uff0c\u4e0b\u8868\u5217\u51fa\u4e86\u6240\u6709\u7684\u5b57\u6bb5\u67e5\u8be2\u53c2\u6570\uff1a<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
          \u5b57\u6bb5\u540d<\/th>\n\u8bf4\u660e<\/th>\n<\/tr>\n<\/thead>\n
          exact<\/span><\/td>\n\u7cbe\u786e\u5339\u914d<\/td>\n<\/tr>\n
          iexact<\/span><\/td>\n\u4e0d\u533a\u5206\u5927\u5c0f\u5199\u7684\u7cbe\u786e\u5339\u914d<\/td>\n<\/tr>\n
          contains<\/span><\/td>\n\u5305\u542b\u5339\u914d<\/td>\n<\/tr>\n
          icontains<\/span><\/td>\n\u4e0d\u533a\u5206\u5927\u5c0f\u5199\u7684\u5305\u542b\u5339\u914d<\/td>\n<\/tr>\n
          in<\/span><\/td>\n\u5728..\u4e4b\u5185\u7684\u5339\u914d<\/td>\n<\/tr>\n
          gt<\/span><\/td>\n\u5927\u4e8e<\/td>\n<\/tr>\n
          gte<\/span><\/td>\n\u5927\u4e8e\u7b49\u4e8e<\/td>\n<\/tr>\n
          lt<\/span><\/td>\n\u5c0f\u4e8e<\/td>\n<\/tr>\n
          lte<\/span><\/td>\n\u5c0f\u4e8e\u7b49\u4e8e<\/td>\n<\/tr>\n
          startswith<\/span><\/td>\n\u4ece\u5f00\u5934\u5339\u914d<\/td>\n<\/tr>\n
          istartswith<\/span><\/td>\n\u4e0d\u533a\u5206\u5927\u5c0f\u5199\u4ece\u5f00\u5934\u5339\u914d<\/td>\n<\/tr>\n
          endswith<\/span><\/td>\n\u4ece\u7ed3\u5c3e\u5904\u5339\u914d<\/td>\n<\/tr>\n
          iendswith<\/span><\/td>\n\u4e0d\u533a\u5206\u5927\u5c0f\u5199\u4ece\u7ed3\u5c3e\u5904\u5339\u914d<\/td>\n<\/tr>\n
          range<\/span><\/td>\n\u8303\u56f4\u5339\u914d<\/td>\n<\/tr>\n
          date<\/span><\/td>\n\u65e5\u671f\u5339\u914d<\/td>\n<\/tr>\n
          year<\/span><\/td>\n\u5e74\u4efd<\/td>\n<\/tr>\n
          iso_year<\/td>\n\u4ee5ISO 8601\u6807\u51c6\u786e\u5b9a\u7684\u5e74\u4efd<\/td>\n<\/tr>\n
          month<\/span><\/td>\n\u6708\u4efd<\/td>\n<\/tr>\n
          day<\/span><\/td>\n\u65e5\u671f<\/td>\n<\/tr>\n
          week<\/span><\/td>\n\u7b2c\u51e0\u5468<\/td>\n<\/tr>\n
          week_day<\/span><\/td>\n\u5468\u51e0<\/td>\n<\/tr>\n
          iso_week_day<\/td>\n\u4ee5ISO 8601\u6807\u51c6\u786e\u5b9a\u7684\u661f\u671f\u51e0<\/td>\n<\/tr>\n
          quarter<\/td>\n\u5b63\u5ea6<\/td>\n<\/tr>\n
          time<\/span><\/td>\n\u65f6\u95f4<\/td>\n<\/tr>\n
          hour<\/span><\/td>\n\u5c0f\u65f6<\/td>\n<\/tr>\n
          minute<\/span><\/td>\n\u5206\u949f<\/td>\n<\/tr>\n
          second<\/span><\/td>\n\u79d2<\/td>\n<\/tr>\n
          regex<\/span><\/td>\n\u533a\u5206\u5927\u5c0f\u5199\u7684\u6b63\u5219\u5339\u914d<\/td>\n<\/tr>\n
          iregex<\/span><\/td>\n\u4e0d\u533a\u5206\u5927\u5c0f\u5199\u7684\u6b63\u5219\u5339\u914d<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
            \n
          • exact<\/span><\/li>\n<\/ul>\n
            \u9ed8\u8ba4\u7c7b\u578b\u3002\u5982\u679c\u4f60\u4e0d\u63d0\u4f9b\u67e5\u8be2\u7c7b\u578b\uff0c\u6216\u8005\u5173\u952e\u5b57\u53c2\u6570\u4e0d\u5305\u542b\u4e00\u4e2a\u53cc\u4e0b\u5212\u7ebf\uff0c\u90a3\u4e48\u67e5\u8be2\u7c7b\u578b\u5c31\u662f\u8fd9\u4e2a\u9ed8\u8ba4\u7684exact\u3002<\/p>\n
            \n
            >>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>headline__exact<\/span>=<\/span>\"Cat bites dog\"<\/span>)<\/span>\r\n# \u76f8\u5f53\u4e8e<\/span>\r\n# SELECT ... WHERE headline = 'Cat bites dog';<\/span>\r\n# \u4e0b\u9762\u4e24\u4e2a\u76f8\u5f53<\/span>\r\n>>><\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id__exact<\/span>=<\/span>14<\/span>)<\/span>  # \u663e\u793a\u6307\u5b9a<\/span>\r\n>>><\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>14<\/span>)<\/span>         # \u9690\u542b__exact<\/span>\r\n<\/pre>\n<\/div>\n
              \n
            • iexact<\/span><\/li>\n<\/ul>\n
              \u4e0d\u533a\u5206\u5927\u5c0f\u5199\u7684\u67e5\u8be2\u3002\u6ce8\u610f\uff1aSQLite3\u6570\u636e\u5e93\u4e0d\u652f\u6301\u5927\u5c0f\u5199\u533a\u5206\u3002<\/p>\n
              \n
              >>><\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>name__iexact<\/span>=<\/span>\"liujiang blog\"<\/span>)<\/span>\r\n# \u5339\u914d\"liujiang Blog\", \"liujiang blog\",\u751a\u81f3\"LIUJIANG blOG\".<\/span>\r\n<\/pre>\n<\/div>\n
                \n
              • contains<\/span><\/li>\n<\/ul>\n
                \u5305\u542b\u7c7b\u578b\u7684\u5339\u914d\u6d4b\u8bd5\uff01\u5927\u5c0f\u5199\u654f\u611f\uff01<\/p>\n
                \n
                Entry<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>headline__contains<\/span>=<\/span>'Lennon'<\/span>)<\/span>\r\n# \u76f8\u5f53\u4e8e<\/span>\r\n# SELECT ... WHERE headline LIKE '%Lennon%';<\/span>\r\n# \u5339\u914d'Today Lennon honored'\uff0c\u4f46\u4e0d\u5339\u914d'today lennon honored'<\/span>\r\n<\/pre>\n<\/div>\n
                  \n
                • icontains<\/span><\/li>\n<\/ul>\n
                  contains\u7684\u5927\u5c0f\u5199\u4e0d\u654f\u611f\u6a21\u5f0f\u3002<\/p>\n
                    \n
                  • startswith\u548cendswith<\/span><\/li>\n<\/ul>\n
                    \u4ee5\u4ec0\u4e48\u5f00\u5934\u548c\u4ee5\u4ec0\u4e48\u7ed3\u5c3e\u3002\u5927\u5c0f\u5199\u654f\u611f\uff01<\/p>\n
                      \n
                    • istartswith\u548ciendswith<\/span><\/li>\n<\/ul>\n
                      \u4e0d\u533a\u5206\u5927\u5c0f\u5199\u7684\u6a21\u5f0f\u3002<\/p>\n
                        \n
                      • in<\/span><\/li>\n<\/ul>\n
                        \u5728\u7ed9\u5b9a\u7684\u5217\u8868\u91cc\u67e5\u627e\u3002<\/p>\n
                        \n
                        Entry.objects.filter(id__in=[1, 3, 4])\r\n<\/pre>\n<\/div>\n
                        \u8fd8\u53ef\u4ee5\u4f7f\u7528\u52a8\u6001\u67e5\u8be2\u96c6\uff0c\u800c\u4e0d\u662f\u63d0\u4f9b\u6587\u5b57\u503c\u5217\u8868\uff1a<\/p>\n
                        \n
                        inner_qs<\/span> =<\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>name__contains<\/span>=<\/span>'jodan'<\/span>)<\/span>  # \u7ed3\u679c\u662f\u4e00\u4e2ablog\u7684queryset<\/span>\r\nentries<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>blog__in<\/span>=<\/span>inner_qs<\/span>)<\/span>  # \u7ed3\u679c\u662f\u4e00\u4e2aentry\u7684queryset<\/span>\r\n<\/pre>\n<\/div>\n
                        \u6216\u8005\u4ecevalues()\u6216values_list()<\/code>\u4e2d\u83b7\u53d6\u7684QuerySet\u4f5c\u4e3a\u6bd4\u5bf9\u7684\u5bf9\u8c61\uff1a<\/p>\n
                        \n
                        inner_qs = Blog.objects.filter(name__contains='Ch').values('name')\r\nentries = Entry.objects.filter(blog__name__in=inner_qs)\r\n<\/pre>\n<\/div>\n
                        \u4e0b\u9762\u7684\u4f8b\u5b50\u5c06\u4ea7\u751f\u4e00\u4e2a\u5f02\u5e38\uff0c\u56e0\u4e3a\u8bd5\u56fe\u63d0\u53d6\u4e24\u4e2a\u5b57\u6bb5\u7684\u503c\uff0c\u4f46\u662f\u67e5\u8be2\u8bed\u53e5\u53ea\u9700\u8981\u4e00\u4e2a\u5b57\u6bb5\u7684\u503c\uff1a<\/p>\n
                        \n
                        # \u9519\u8bef\u7684\u5b9e\u4f8b\uff0c\u5c06\u5f39\u51fa\u5f02\u5e38\u3002\r\ninner_qs = Blog.objects.filter(name__contains='Ch').values('name', 'id')\r\nentries = Entry.objects.filter(blog__name__in=inner_qs)\r\n<\/pre>\n<\/div>\n
                          \n
                        • gt<\/span><\/li>\n<\/ul>\n
                          \u5927\u4e8e<\/p>\n
                          \n
                          Entry.objects.filter(id__gt=4)\r\n<\/pre>\n<\/div>\n
                            \n
                          • gte<\/li>\n<\/ul>\n
                            \u5927\u4e8e\u6216\u7b49\u4e8e<\/p>\n
                              \n
                            • lt<\/li>\n<\/ul>\n
                              \u5c0f\u4e8e<\/p>\n
                                \n
                              • lte<\/li>\n<\/ul>\n
                                \u5c0f\u4e8e\u6216\u7b49\u4e8e<\/p>\n
                                  \n
                                • range<\/li>\n<\/ul>\n
                                  \u8303\u56f4\u6d4b\u8bd5\uff08\u5305\u542b\u4e8e\u4e4b\u4e2d\uff09\u3002<\/p>\n
                                  \n
                                  import<\/span> datetime<\/span>\r\nstart_date<\/span> =<\/span> datetime<\/span>.<\/span>date<\/span>(<\/span>2005<\/span>,<\/span> 1<\/span>,<\/span> 1<\/span>)<\/span>\r\nend_date<\/span> =<\/span> datetime<\/span>.<\/span>date<\/span>(<\/span>2005<\/span>,<\/span> 3<\/span>,<\/span> 31<\/span>)<\/span>\r\nEntry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>pub_date__range<\/span>=<\/span>(<\/span>start_date<\/span>,<\/span> end_date<\/span>))<\/span>\r\n<\/pre>\n<\/div>\n
                                  \u8b66\u544a:\u8fc7\u6ee4\u5177\u6709\u65e5\u671f\u7684DateTimeField\u4e0d\u4f1a\u5305\u542b\u6700\u540e\u4e00\u5929\uff0c\u56e0\u4e3a\u8fb9\u754c\u88ab\u89e3\u91ca\u4e3a\u201c\u7ed9\u5b9a\u65e5\u671f\u76840am\u201d\u3002<\/p>\n
                                    \n
                                  • date<\/li>\n<\/ul>\n
                                    \u8fdb\u884c\u65e5\u671f\u5bf9\u6bd4\u3002<\/p>\n
                                    \n
                                    Entry.objects.filter(pub_date__date=datetime.date(2005, 1, 1))\r\nEntry.objects.filter(pub_date__date__gt=datetime.date(2005, 1, 1))\r\n<\/pre>\n<\/div>\n
                                    \u5f53USE_TZ<\/code>\u4e3aTrue\u65f6\uff0c\u5b57\u6bb5\u5c06\u8f6c\u6362\u4e3a\u5f53\u524d\u65f6\u533a\uff0c\u7136\u540e\u8fdb\u884c\u8fc7\u6ee4\u3002<\/p>\n
                                      \n
                                    • year<\/li>\n<\/ul>\n
                                      \u5bf9\u5e74\u4efd\u8fdb\u884c\u5339\u914d\u3002<\/p>\n
                                      \n
                                      Entry.objects.filter(pub_date__year=2005)\r\nEntry.objects.filter(pub_date__year__gte=2005)\r\n<\/pre>\n<\/div>\n
                                      \u5f53USE_TZ<\/code>\u4e3aTrue\u65f6\uff0c\u5728\u8fc7\u6ee4\u4e4b\u524d\uff0cdatetime\u5b57\u6bb5\u5c06\u8f6c\u6362\u4e3a\u5f53\u524d\u65f6\u533a\u3002<\/p>\n
                                        \n
                                      • iso_year<\/li>\n<\/ul>\n
                                        \u4ee5ISO 8601\u6807\u51c6\u786e\u8ba4\u7684\u5e74\u4efd\u3002\u6574\u6570\u7c7b\u578b\u3002<\/p>\n
                                        \n
                                        Entry.objects.filter(pub_date__iso_year=2005)\r\nEntry.objects.filter(pub_date__iso_year__gte=2005)\r\n<\/pre>\n<\/div>\n
                                          \n
                                        • month<\/li>\n<\/ul>\n
                                          \u5bf9\u6708\u4efd\u8fdb\u884c\u5339\u914d\u3002\u53d6\u6574\u65701\uff081\u6708\uff09\u81f312\uff0812\u6708\uff09\u3002<\/p>\n
                                          \n
                                          Entry.objects.filter(pub_date__month=12)\r\nEntry.objects.filter(pub_date__month__gte=6)\r\n<\/pre>\n<\/div>\n
                                          \u5f53USE_TZ\u4e3aTrue\u65f6\uff0c\u5728\u8fc7\u6ee4\u4e4b\u524d\uff0cdatetime\u5b57\u6bb5\u5c06\u8f6c\u6362\u4e3a\u5f53\u524d\u65f6\u533a\u3002<\/p>\n
                                            \n
                                          • day<\/li>\n<\/ul>\n
                                            \u5bf9\u5177\u4f53\u5230\u67d0\u4e00\u5929\u7684\u5339\u914d\u3002<\/p>\n
                                            \n
                                            Entry.objects.filter(pub_date__day=3)\r\nEntry.objects.filter(pub_date__day__gte=3)\r\n<\/pre>\n<\/div>\n
                                            \u5f53USE_TZ\u4e3aTrue\u65f6\uff0c\u5728\u8fc7\u6ee4\u4e4b\u524d\uff0cdatetime\u5b57\u6bb5\u5c06\u8f6c\u6362\u4e3a\u5f53\u524d\u65f6\u533a\u3002<\/p>\n
                                              \n
                                            • week<\/li>\n<\/ul>\n
                                              \u6839\u636eISO-8601\u8fd4\u56de\u5468\u53f7\uff081-52\u621653\uff09\uff0c\u5373\u661f\u671f\u4e00\u5f00\u59cb\u7684\u661f\u671f\uff0c\u661f\u671f\u56db\u6216\u4e4b\u524d\u7684\u7b2c\u4e00\u5468\u3002<\/p>\n
                                              \n
                                              Entry.objects.filter(pub_date__week=52)\r\nEntry.objects.filter(pub_date__week__gte=32, pub_date__week__lte=38)\r\n<\/pre>\n<\/div>\n
                                              \u5f53USE_TZ\u4e3aTrue\u65f6\uff0c\u5b57\u6bb5\u5c06\u8f6c\u6362\u4e3a\u5f53\u524d\u65f6\u533a\uff0c\u7136\u540e\u8fdb\u884c\u8fc7\u6ee4\u3002<\/p>\n
                                                \n
                                              • week_day<\/li>\n<\/ul>\n
                                                \u8fdb\u884c\u201c\u661f\u671f\u51e0\u201d\u5339\u914d\u3002 \u53d6\u6574\u6570\u503c\uff0c\u661f\u671f\u65e5\u4e3a1\uff0c\u661f\u671f\u4e00\u4e3a2\uff0c\u661f\u671f\u516d\u4e3a7\u3002<\/p>\n
                                                \n
                                                Entry.objects.filter(pub_date__week_day=2)\r\nEntry.objects.filter(pub_date__week_day__gte=2)\r\n<\/pre>\n<\/div>\n
                                                \u5f53USE_TZ\u4e3aTrue\u65f6\uff0c\u5728\u8fc7\u6ee4\u4e4b\u524d\uff0cdatetime\u5b57\u6bb5\u5c06\u8f6c\u6362\u4e3a\u5f53\u524d\u65f6\u533a\u3002<\/p>\n
                                                  \n
                                                • iso_week_day<\/li>\n<\/ul>\n
                                                  \u4ee5ISO8601\u6807\u51c6\u786e\u5b9a\u7684\u661f\u671f\u51e0\u3002\u53d6\u503c\u8303\u56f41-7\uff0c\u5206\u522b\u8868\u793a\u661f\u671f\u4e00\u5230\u661f\u671f\u65e5\u3002<\/p>\n
                                                  \n
                                                  Entry.objects.filter(pub_date__iso_week_day=1)\r\nEntry.objects.filter(pub_date__iso_week_day__gte=1)\r\n<\/pre>\n<\/div>\n
                                                    \n
                                                  • quarter<\/li>\n<\/ul>\n
                                                    \u5b63\u5ea6\u3002\u53d6\u503c\u8303\u56f41-4\u3002<\/p>\n
                                                    \n
                                                    Entry.objects.filter(pub_date__quarter=2)\r\n<\/pre>\n<\/div>\n
                                                      \n
                                                    • time<\/li>\n<\/ul>\n
                                                      \u5c06\u5b57\u6bb5\u7684\u503c\u8f6c\u4e3adatetime.time\u683c\u5f0f\u5e76\u8fdb\u884c\u5bf9\u6bd4\u3002<\/p>\n
                                                      \n
                                                      Entry.objects.filter(pub_date__time=datetime.time(14, 30))\r\nEntry.objects.filter(pub_date__time__between=(datetime.time(8), datetime.time(17)))\r\n<\/pre>\n<\/div>\n
                                                      USE_TZ\u4e3aTrue\u65f6\uff0c\u5b57\u6bb5\u5c06\u8f6c\u6362\u4e3a\u5f53\u524d\u65f6\u533a\uff0c\u7136\u540e\u8fdb\u884c\u8fc7\u6ee4\u3002<\/p>\n
                                                        \n
                                                      • hour<\/li>\n<\/ul>\n
                                                        \u5bf9\u5c0f\u65f6\u8fdb\u884c\u5339\u914d\u3002 \u53d60\u548c23\u4e4b\u95f4\u7684\u6574\u6570\u3002<\/p>\n
                                                        \n
                                                        Event.objects.filter(timestamp__hour=23)\r\nEvent.objects.filter(time__hour=5)\r\nEvent.objects.filter(timestamp__hour__gte=12)\r\n<\/pre>\n<\/div>\n
                                                        \u5f53USE_TZ\u4e3aTrue\u65f6\uff0c\u503c\u5c06\u8fc7\u6ee4\u524d\u8f6c\u6362\u4e3a\u5f53\u524d\u65f6\u533a\u3002<\/p>\n
                                                          \n
                                                        • minute<\/li>\n<\/ul>\n
                                                          \u5bf9\u5206\u949f\u5339\u914d\u3002\u53d60\u548c59\u4e4b\u95f4\u7684\u6574\u6570\u3002<\/p>\n
                                                          \n
                                                          Event.objects.filter(timestamp__minute=29)\r\nEvent.objects.filter(time__minute=46)\r\nEvent.objects.filter(timestamp__minute__gte=29)\r\n<\/pre>\n<\/div>\n
                                                          \u5f53USE_TZ\u4e3aTrue\u65f6\uff0c\u503c\u5c06\u88ab\u8fc7\u6ee4\u524d\u8f6c\u6362\u4e3a\u5f53\u524d\u65f6\u533a\u3002<\/p>\n
                                                            \n
                                                          • second<\/li>\n<\/ul>\n
                                                            \u5bf9\u79d2\u6570\u8fdb\u884c\u5339\u914d\u3002\u53d60\u548c59\u4e4b\u95f4\u7684\u6574\u6570\u3002<\/p>\n
                                                            \n
                                                            Event.objects.filter(timestamp__second=31)\r\nEvent.objects.filter(time__second=2)\r\nEvent.objects.filter(timestamp__second__gte=31)\r\n<\/pre>\n<\/div>\n
                                                            \u5f53USE_TZ\u4e3aTrue\u65f6\uff0c\u503c\u5c06\u8fc7\u6ee4\u524d\u8f6c\u6362\u4e3a\u5f53\u524d\u65f6\u533a\u3002<\/p>\n
                                                              \n
                                                            • regex<\/li>\n<\/ul>\n
                                                              \u533a\u5206\u5927\u5c0f\u5199\u7684\u6b63\u5219\u8868\u8fbe\u5f0f\u5339\u914d\u3002<\/p>\n
                                                              \n
                                                              Entry.objects.get(title__regex=r'^(An?|The) +')\r\n<\/pre>\n<\/div>\n
                                                              \u5efa\u8bae\u4f7f\u7528\u539f\u59cb\u5b57\u7b26\u4e32\uff08\u4f8b\u5982\uff0cr’foo’\u800c\u4e0d\u662f’foo’\uff09\u6765\u4f20\u9012\u6b63\u5219\u8868\u8fbe\u5f0f\u8bed\u6cd5\u3002<\/p>\n
                                                                \n
                                                              • iregex<\/li>\n<\/ul>\n
                                                                \u4e0d\u533a\u5206\u5927\u5c0f\u5199\u7684\u6b63\u5219\u8868\u8fbe\u5f0f\u5339\u914d\u3002<\/p>\n
                                                                \n
                                                                Entry.objects.get(title__iregex=r'^(an?|the) +')\r\n<\/pre>\n<\/div>\n
                                                                7. \u8de8\u8d8a\u5173\u7cfb\u67e5\u8be2<\/h2>\n
                                                                Django\u63d0\u4f9b\u4e86\u5f3a\u5927\u5e76\u4e14\u76f4\u89c2\u7684\u65b9\u5f0f\u89e3\u51b3\u8de8\u8d8a\u5173\u8054\u7684\u67e5\u8be2\uff0c\u5b83\u5728\u540e\u53f0\u81ea\u52a8\u6267\u884c\u5305\u542bJOIN\u7684SQL\u8bed\u53e5\u3002\u8981\u8de8\u8d8a\u67d0\u4e2a\u5173\u8054\uff0c\u53ea\u9700\u4f7f\u7528\u5173\u8054\u7684\u6a21\u578b\u5b57\u6bb5\u540d\u79f0\uff0c\u5e76\u4f7f\u7528\u53cc\u4e0b\u5212\u7ebf\u5206\u9694\uff0c\u76f4\u81f3\u4f60\u60f3\u8981\u7684\u5b57\u6bb5\uff08\u53ef\u4ee5\u94fe\u5f0f\u8de8\u8d8a\uff0c\u65e0\u9650\u8de8\u5ea6\uff09\u3002\u4f8b\u5982\uff1a<\/p>\n
                                                                \n
                                                                # \u8fd4\u56de\u6240\u6709Blog\u7684name\u4e3a'Beatles Blog'\u7684Entry\u5bf9\u8c61<\/span>\r\n# \u4e00\u5b9a\u8981\u6ce8\u610f\uff0c\u8fd4\u56de\u7684\u662fEntry\u5bf9\u8c61\uff0c\u800c\u4e0d\u662fBlog\u5bf9\u8c61\u3002<\/span>\r\n# objects\u524d\u9762\u7528\u7684\u662f\u54ea\u4e2aclass\uff0c\u8fd4\u56de\u7684\u5c31\u662f\u54ea\u4e2aclass\u7684\u5bf9\u8c61\u3002<\/span>\r\n>>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>blog__name<\/span>=<\/span>'Beatles Blog'<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                \u53cd\u4e4b\u4ea6\u7136\uff0c\u5982\u679c\u8981\u5f15\u7528\u4e00\u4e2a\u53cd\u5411\u5173\u8054\uff0c\u53ea\u9700\u8981\u4f7f\u7528\u6a21\u578b\u7684\u5c0f\u5199\u540d!<\/p>\n
                                                                \n
                                                                # \u83b7\u53d6\u6240\u6709\u7684Blog\u5bf9\u8c61\uff0c\u524d\u63d0\u662f\u5b83\u6240\u5173\u8054\u7684Entry\u7684headline\u5305\u542b'Lennon'<\/span>\r\n>>><\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>entry__headline__contains<\/span>=<\/span>'Lennon'<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                \u5982\u679c\u4f60\u5728\u591a\u7ea7\u5173\u8054\u4e2d\u8fdb\u884c\u8fc7\u6ee4\u800c\u4e14\u5176\u4e2d\u67d0\u4e2a\u4e2d\u95f4\u6a21\u578b\u6ca1\u6709\u6ee1\u8db3\u8fc7\u6ee4\u6761\u4ef6\u7684\u503c\uff0cDjango\u5c06\u628a\u5b83\u5f53\u505a\u4e00\u4e2a\u7a7a\u7684\uff08\u6240\u6709\u7684\u503c\u90fd\u4e3aNULL\uff09\u4f46\u662f\u5408\u6cd5\u7684\u5bf9\u8c61\uff0c\u4e0d\u4f1a\u629b\u51fa\u4efb\u4f55\u5f02\u5e38\u6216\u9519\u8bef\u3002\u4f8b\u5982\uff0c\u5728\u4e0b\u9762\u7684\u8fc7\u6ee4\u5668\u4e2d\uff1a<\/p>\n
                                                                \n
                                                                Blog.objects.filter(entry__authors__name='Lennon')\r\n<\/pre>\n<\/div>\n
                                                                \u5982\u679cEntry\u4e2d\u6ca1\u6709\u5173\u8054\u4efb\u4f55\u7684author\uff0c\u90a3\u4e48\u5b83\u5c06\u5f53\u4f5c\u5176\u6ca1\u6709name\uff0c\u800c\u4e0d\u4f1a\u56e0\u4e3a\u6ca1\u6709author \u5f15\u53d1\u4e00\u4e2a\u9519\u8bef\u3002\u901a\u5e38\uff0c\u8fd9\u662f\u6bd4\u8f83\u7b26\u5408\u903b\u8f91\u7684\u5904\u7406\u65b9\u5f0f\u3002\u552f\u4e00\u53ef\u80fd\u8ba9\u4f60\u56f0\u60d1\u7684\u662f\u5f53\u4f60\u4f7f\u7528isnull<\/code>\u7684\u65f6\u5019\uff1a<\/p>\n
                                                                \n
                                                                Blog.objects.filter(entry__authors__name__isnull=True)\r\n<\/pre>\n<\/div>\n
                                                                \u8fd9\u5c06\u8fd4\u56deBlog\u5bf9\u8c61\uff0c\u5b83\u5173\u8054\u7684entry\u5bf9\u8c61\u7684author\u5b57\u6bb5\u7684name\u5b57\u6bb5\u4e3a\u7a7a\uff0c\u4ee5\u53caEntry\u5bf9\u8c61\u7684author\u5b57\u6bb5\u4e3a\u7a7a\u3002\u5982\u679c\u4f60\u4e0d\u9700\u8981\u540e\u8005\uff0c\u4f60\u53ef\u4ee5\u8fd9\u6837\u5199\uff1a<\/p>\n
                                                                \n
                                                                Blog.objects.filter(entry__authors__isnull=False,entry__authors__name__isnull=True)\r\n<\/pre>\n<\/div>\n
                                                                \u8de8\u8d8a\u591a\u503c\u7684\u5173\u7cfb\u67e5\u8be2<\/span><\/p>\n
                                                                \u6700\u57fa\u672c\u7684filter\u548cexclude\u7684\u5173\u952e\u5b57\u53c2\u6570\u53ea\u6709\u4e00\u4e2a\uff0c\u8fd9\u79cd\u60c5\u51b5\u5f88\u597d\u7406\u89e3\u3002\u4f46\u662f\u5f53\u5173\u952e\u5b57\u53c2\u6570\u6709\u591a\u4e2a\uff0c\u4e14\u662f\u8de8\u8d8a\u5916\u952e\u6216\u8005\u591a\u5bf9\u591a\u7684\u60c5\u51b5\u4e0b\uff0c\u90a3\u4e48\u5c31\u6bd4\u8f83\u590d\u6742\uff0c\u8ba9\u4eba\u8ff7\u60d1\u4e86\u3002\u6211\u4eec\u770b\u4e0b\u9762\u7684\u4f8b\u5b50\uff1a<\/p>\n
                                                                \n
                                                                Blog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>entry__headline__contains<\/span>=<\/span>'Lennon'<\/span>,<\/span> entry__pub_date__year<\/span>=<\/span>2008<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                \u8fd9\u662f\u4e00\u4e2a\u8de8\u5916\u952e\u3001\u4e24\u4e2a\u8fc7\u6ee4\u53c2\u6570\u7684\u67e5\u8be2\u3002\u6b64\u65f6\u6211\u4eec\u7406\u89e3\u4e24\u4e2a\u53c2\u6570\u4e4b\u95f4\u5c5e\u4e8e-\u4e0e\u201cand\u201d\u7684\u5173\u7cfb\uff0c\u4e5f\u5c31\u662f\u8bf4\uff0c\u8fc7\u6ee4\u51fa\u6765\u7684BLog\u5bf9\u8c61\u5bf9\u5e94\u7684entry\u5bf9\u8c61\u5fc5\u987b\u540c\u65f6\u6ee1\u8db3\u4e0a\u9762\u4e24\u4e2a\u6761\u4ef6\u3002\u8fd9\u70b9\u5f88\u597d\u7406\u89e3\u3002\u4e5f\u5c31\u662f\u8bf4\u4e0a\u9762\u8981\u6c42entry\u540c\u65f6\u6ee1\u8db3\u4e24\u4e2a\u6761\u4ef6<\/span>\u3002<\/p>\n
                                                                \u4f46\u662f\uff0c\u5f53\u91c7\u7528\u94fe\u5f0f\u8fc7\u6ee4\u5c31\u4e0d\u4e00\u6837\u4e86\u3002<\/p>\n
                                                                \u5047\u8bbe\u53ea\u6709\u4e00\u4e2a\u535a\u5ba2\uff0c\u53d6\u540da\uff0c\u4e0e\u5b83\u5173\u8054\u7684\u6587\u7ae0\u4e2d\u6709\u4e00\u4e9b\u6807\u9898\u542b\u6709 “Lennon” \u4f46\u4e0d\u662f2008\u5e74\u53d1\u5e03\u7684\uff0c\u6709\u4e00\u4e9b\u662f2008\u5e74\u53d1\u5e03\u4f46\u6807\u9898\u4e0d\u5305\u542b”Lennon”\uff0c\u6ca1\u67092008\u5e74\u53d1\u5e03\u6807\u9898\u5305\u542b”Lennon”\u7684\u6587\u7ae0\u3002\u770b\u4e0b\u9762\u7684\u7528\u6cd5\uff1a<\/p>\n
                                                                \n
                                                                Blog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>entry__headline__contains<\/span>=<\/span>'Lennon'<\/span>)<\/span>.<\/span>filter<\/span>(<\/span>entry__pub_date__year<\/span>=<\/span>2008<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                  \n
                                                                • Blog.objects.filter(entry__headline__contains='Lennon')<\/code>\u7684\u7ed3\u679c\u662fa<\/li>\n
                                                                • a.filter(entry__pub_date__year=2008)<\/code>\u7684\u7ed3\u679c\u4f9d\u7136\u662fa<\/li>\n<\/ul>\n
                                                                  \u6240\u4ee5Blog.objects.filter(entry__headline__contains='Lennon').filter(entry__pub_date__year=2008)<\/code>\u7684\u7ed3\u679c\u6700\u7ec8\u662fa\u3002<\/p>\n
                                                                  \u7406\u89e3\u8fd9\u4e2a\u7ed3\u679c\u7684\u6838\u5fc3\u662f\u8981\u7406\u89e3\u7b2c\u4e00\u4e2afilter\u7684\u8fc7\u6ee4\u96c6\u5408\u8fd4\u56de\u7684\u662fBlog\u800c\u4e0d\u662fEntry\u5b9e\u4f8b\uff0c\u4e0d\u662f\u8fc7\u6ee4\u4e86Entry\uff0c\u800c\u662f\u8fc7\u6ee4\u4e86Blog\u3002<\/p>\n
                                                                  \u4f46\u6b64\u65f6Blog.objects.filter(entry__headline__contains=’Lennon’, entry__pub_date__year=2008)\u7684\u7ed3\u679c\u662f\u7a7a\u96c6\u3002<\/p>\n
                                                                  \u628a\u4e24\u4e2a\u53c2\u6570\u62c6\u5f00\uff0c\u653e\u5728\u4e24\u4e2afilter\u8c03\u7528\u91cc\u9762\uff0c\u6309\u7167\u6211\u4eec\u524d\u9762\u8bf4\u8fc7\u7684\u94fe\u5f0f\u8fc7\u6ee4\uff0c\u6211\u4eec\u60f3\u5f53\u7136\u7684\u8ba4\u4e3a\u7ed3\u679c\u5e94\u8be5\u548c\u4e0a\u9762\u7684\u4f8b\u5b50\u4e00\u6837\u3002\u53ef\u5b9e\u9645\u4e0a\uff0c\u5b83\u4e0d\u4e00\u6837\uff0c\u8fd9\u771f\u662f\u8ba9\u4eba\u5934\u75bc\u3002<\/p>\n
                                                                  \u591a\u5bf9\u591a\u5173\u7cfb\u4e0b\u7684\u591a\u503c\u67e5\u8be2\u548c\u5916\u952eforeignkey\u7684\u60c5\u51b5\u4e00\u6837\u3002<\/p>\n
                                                                  \u4f46\u662f\uff0c\u66f4\u5934\u75bc\u7684\u6765\u4e86\uff0c\u770b\u770bexclude\u7684\u60c5\u51b5\uff01<\/p>\n
                                                                  \n
                                                                  Blog<\/span>.<\/span>objects<\/span>.<\/span>exclude<\/span>(<\/span>entry__headline__contains<\/span>=<\/span>'Lennon'<\/span>,<\/span>entry__pub_date__year<\/span>=<\/span>2008<\/span>,)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                  \u8fd9\u4f1a\u6392\u9664\u4e00\u4e9bblog\uff0c\u8fd9\u4e9bblog\u7684\u5173\u8054\u6587\u7ae0\u4e2d\u540c\u65f6\u6709\u4e0b\u9762\u4e24\u79cd\u7c7b\u578b\uff1a<\/p>\n
                                                                    \n
                                                                  • headline\u4e2d\u5305\u542b\u201cLennon\u201d<\/li>\n
                                                                  • \u57282008\u5e74\u53d1\u5e03\u7684<\/li>\n<\/ul>\n
                                                                    \u800c\u4e0d\u7ba1\u5173\u8054\u6587\u7ae0\u4e2d\u662f\u5426\u6709\u540c\u65f6\u5177\u5907\u4ee5\u4e0a\u4e24\u4e2a\u6761\u4ef6\u7684\u6587\u7ae0\u3002<\/p>\n
                                                                    \u90a3\u4e48\u8981\u6392\u9664\u5173\u8054\u6709\u540c\u65f6\u6ee1\u8db3\u4e0a\u9762\u4e24\u4e2a\u6761\u4ef6\u7684\u6587\u7ae0\u7684blog\uff0c\u8be5\u600e\u4e48\u529e\u5462\uff1f\u770b\u4e0b\u9762\uff1a<\/p>\n
                                                                    \n
                                                                    Blog<\/span>.<\/span>objects<\/span>.<\/span>exclude<\/span>(<\/span>\r\nentry<\/span>=<\/span>Entry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>\r\n    headline__contains<\/span>=<\/span>'Lennon'<\/span>,<\/span>\r\n    pub_date__year<\/span>=<\/span>2008<\/span>,<\/span>\r\n),<\/span>\r\n)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \uff08\u6709\u6ca1\u6709\u5f88\u5751\u7239\u7684\u611f\u89c9\uff1f\u6240\u4ee5\uff0c\u5efa\u8bae\u5728\u78b0\u5230\u8de8\u5173\u7cfb\u7684\u591a\u503c\u67e5\u8be2\u65f6\uff0c\u5c3d\u91cf\u4f7f\u7528Q\u67e5\u8be2\uff09<\/p>\n
                                                                    8. F\u8868\u8fbe\u5f0f<\/h2>\n
                                                                    \u5230\u76ee\u524d\u4e3a\u6b62\u7684\u4f8b\u5b50\u4e2d\uff0c\u6211\u4eec\u90fd\u662f\u5c06\u6a21\u578b\u5b57\u6bb5\u4e0e\u5e38\u91cf\u8fdb\u884c\u6bd4\u8f83\u3002\u4f46\u662f\uff0c\u5982\u679c\u4f60\u60f3\u5c06\u6a21\u578b\u7684\u4e00\u4e2a\u5b57\u6bb5\u4e0e\u540c\u4e00\u4e2a\u6a21\u578b\u7684\u53e6\u5916\u4e00\u4e2a\u5b57\u6bb5\u8fdb\u884c\u6bd4\u8f83\u8be5\u600e\u4e48\u529e\uff1f<\/p>\n
                                                                    \u4f7f\u7528Django\u63d0\u4f9b\u7684F\u8868\u8fbe\u5f0f\uff01<\/p>\n
                                                                    \u4f8b\u5982\uff0c\u4e3a\u4e86\u67e5\u627ecomments\u6570\u76ee\u591a\u4e8epingbacks\u6570\u76ee\u7684Entry\uff0c\u53ef\u4ee5\u6784\u9020\u4e00\u4e2aF()<\/code>\u5bf9\u8c61\u6765\u5f15\u7528pingback\u6570\u76ee\uff0c\u5e76\u5728\u67e5\u8be2\u4e2d\u4f7f\u7528\u8be5F()\u5bf9\u8c61\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> from<\/span> django.db.models<\/span> import<\/span> F<\/span>\r\n>>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>number_of_comments__gt<\/span>=<\/span>F<\/span>(<\/span>'number_of_pingbacks'<\/span>))<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    Django\u652f\u6301\u5bf9F()\u5bf9\u8c61\u8fdb\u884c\u52a0\u3001\u51cf\u3001\u4e58\u3001\u9664\u3001\u6c42\u4f59\u4ee5\u53ca\u5e42\u8fd0\u7b97\u7b49\u7b97\u672f\u64cd\u4f5c\u3002\u4e24\u4e2a\u64cd\u4f5c\u6570\u53ef\u4ee5\u662f\u5e38\u6570\u548c\u5176\u5b83F()\u5bf9\u8c61\u3002<\/p>\n
                                                                    \u4f8b\u5982\u67e5\u627ecomments\u6570\u76ee\u6bd4pingbacks\u4e24\u500d\u8fd8\u8981\u591a\u7684Entry\uff0c\u6211\u4eec\u53ef\u4ee5\u8fd9\u4e48\u5199\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>number_of_comments__gt<\/span>=<\/span>F<\/span>(<\/span>'number_of_pingbacks'<\/span>)<\/span> *<\/span> 2<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u4e3a\u4e86\u67e5\u8be2rating\u6bd4pingback\u548ccomment\u6570\u76ee\u603b\u548c\u8981\u5c0f\u7684Entry\uff0c\u6211\u4eec\u53ef\u4ee5\u8fd9\u4e48\u5199\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>rating__lt<\/span>=<\/span>F<\/span>(<\/span>'number_of_comments'<\/span>)<\/span> +<\/span> F<\/span>(<\/span>'number_of_pingbacks'<\/span>))<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u4f60\u8fd8\u53ef\u4ee5\u5728F()\u4e2d\u4f7f\u7528\u53cc\u4e0b\u5212\u7ebf\u6765\u8fdb\u884c\u8de8\u8868\u67e5\u8be2\u3002\u4f8b\u5982\uff0c\u67e5\u8be2author\u7684\u540d\u5b57\u4e0eblog\u540d\u5b57\u76f8\u540c\u7684Entry\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>authors__name<\/span>=<\/span>F<\/span>(<\/span>'blog__name'<\/span>))<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u5bf9\u4e8edate\u548cdate\/time\u5b57\u6bb5\uff0c\u8fd8\u53ef\u4ee5\u52a0\u6216\u51cf\u53bb\u4e00\u4e2atimedelta\u5bf9\u8c61\u3002\u4e0b\u9762\u7684\u4f8b\u5b50\u5c06\u8fd4\u56de\u53d1\u5e03\u65f6\u95f4\u8d85\u8fc73\u5929\u540e\u88ab\u4fee\u6539\u7684\u6240\u6709Entry\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> from<\/span> datetime<\/span> import<\/span> timedelta<\/span>\r\n>>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>mod_date__gt<\/span>=<\/span>F<\/span>(<\/span>'pub_date'<\/span>)<\/span> +<\/span> timedelta<\/span>(<\/span>days<\/span>=<\/span>3<\/span>))<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    F()\u5bf9\u8c61\u8fd8\u652f\u6301.bitand()<\/code>\u3001.bitor()<\/code>\u3001.bitxor()<\/code>\u3001.bitrightshift()<\/code>\u548c.bitleftshift()<\/code>\u7b49\u4f4d\u64cd\u4f5c\uff0c\u4f8b\u5982\uff1a<\/p>\n
                                                                    \n
                                                                    >>> F('somefield').bitand(16)\r\n<\/pre>\n<\/div>\n
                                                                    9. pk<\/h2>\n
                                                                    pk\u5c31\u662fprimary key<\/code>\u7684\u7f29\u5199\u3002\u901a\u5e38\u60c5\u51b5\u4e0b\uff0c\u4e00\u4e2a\u6a21\u578b\u7684\u4e3b\u952e\u4e3a\u201cid\u201d\uff0c\u6240\u4ee5\u4e0b\u9762\u4e09\u4e2a\u8bed\u53e5\u7684\u6548\u679c\u4e00\u6837\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id__exact<\/span>=<\/span>14<\/span>)<\/span> # Explicit form<\/span>\r\n>>><\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>14<\/span>)<\/span> # __exact is implied<\/span>\r\n>>><\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>pk<\/span>=<\/span>14<\/span>)<\/span> # pk implies id__exact<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u53ef\u4ee5\u8054\u5408\u5176\u4ed6\u7c7b\u578b\u7684\u53c2\u6570\uff1a<\/p>\n
                                                                    \n
                                                                    # Get blogs entries with id 1, 4 and 7<\/span>\r\n>>><\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>pk__in<\/span>=<\/span>[<\/span>1<\/span>,<\/span>4<\/span>,<\/span>7<\/span>])<\/span>\r\n# Get all blog entries with id > 14<\/span>\r\n>>><\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>pk__gt<\/span>=<\/span>14<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u53ef\u4ee5\u8de8\u8868\u64cd\u4f5c\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>blog__id__exact<\/span>=<\/span>3<\/span>)<\/span> \r\n>>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>blog__id<\/span>=<\/span>3<\/span>)<\/span> \r\n>>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>blog__pk<\/span>=<\/span>3<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \uff08\u5f53\u4e3b\u952e\u4e0d\u662fid\u7684\u65f6\u5019\uff0c\u8bf7\u6ce8\u610f\u4e86\uff01<\/span>\uff09<\/p>\n
                                                                    10. \u8f6c\u4e49\u767e\u5206\u7b26\u53f7\u548c\u4e0b\u5212\u7ebf<\/h2>\n
                                                                    \u5728\u539f\u751fSQL\u8bed\u53e5\u4e2d%<\/code>\u7b26\u53f7\u6709\u7279\u6b8a\u7684\u4f5c\u7528\u3002Django\u5e2e\u4f60\u81ea\u52a8\u8f6c\u4e49\u4e86\u767e\u5206\u7b26\u53f7\u548c\u4e0b\u5212\u7ebf\uff0c\u4f60\u53ef\u4ee5\u548c\u666e\u901a\u5b57\u7b26\u4e00\u6837\u4f7f\u7528\u5b83\u4eec\uff0c\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>headline__contains<\/span>=<\/span>'%'<\/span>)<\/span>\r\n# \u5b83\u548c\u4e0b\u9762\u7684\u4e00\u6837<\/span>\r\n# SELECT ... WHERE headline LIKE '%\\%%';<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    11. \u7f13\u5b58\u4e0e\u67e5\u8be2\u96c6<\/h2>\n
                                                                    \u6bcf\u4e2aQuerySet\u90fd\u5305\u542b\u4e00\u4e2a\u7f13\u5b58\uff0c\u7528\u4e8e\u51cf\u5c11\u5bf9\u6570\u636e\u5e93\u7684\u5b9e\u9645\u64cd\u4f5c\u3002\u7406\u89e3\u8fd9\u4e2a\u6982\u5ff5\uff0c\u6709\u52a9\u4e8e\u4f60\u63d0\u9ad8\u67e5\u8be2\u6548\u7387\u3002<\/p>\n
                                                                    \u5bf9\u4e8e\u65b0\u521b\u5efa\u7684QuerySet\uff0c\u5b83\u7684\u7f13\u5b58\u662f\u7a7a\u7684\u3002\u5f53QuerySet\u7b2c\u4e00\u6b21\u88ab\u63d0\u4ea4\u540e\uff0c\u6570\u636e\u5e93\u6267\u884c\u5b9e\u9645\u7684\u67e5\u8be2\u64cd\u4f5c\uff0cDjango\u4f1a\u628a\u67e5\u8be2\u7684\u7ed3\u679c\u4fdd\u5b58\u5728QuerySet\u7684\u7f13\u5b58\u5185\uff0c\u968f\u540e\u7684\u5bf9\u4e8e\u8be5QuerySet\u7684\u63d0\u4ea4\u5c06\u91cd\u7528\u8fd9\u4e2a\u7f13\u5b58\u7684\u6570\u636e\u3002<\/p>\n
                                                                    \u8981\u60f3\u9ad8\u6548\u7684\u5229\u7528\u67e5\u8be2\u7ed3\u679c\uff0c\u964d\u4f4e\u6570\u636e\u5e93\u8d1f\u8f7d\uff0c\u4f60\u5fc5\u987b\u5584\u4e8e\u5229\u7528\u7f13\u5b58\u3002\u770b\u4e0b\u9762\u7684\u4f8b\u5b50\uff0c\u8fd9\u4f1a\u9020\u62102\u6b21\u5b9e\u9645\u7684\u6570\u636e\u5e93\u64cd\u4f5c\uff0c\u52a0\u500d\u6570\u636e\u5e93\u7684\u8d1f\u8f7d\uff0c\u540c\u65f6\u7531\u4e8e\u65f6\u95f4\u5dee\u7684\u95ee\u9898\uff0c\u53ef\u80fd\u5728\u4e24\u6b21\u64cd\u4f5c\u4e4b\u95f4\u6570\u636e\u88ab\u5220\u9664\u6216\u4fee\u6539\u6216\u6dfb\u52a0\uff0c\u5bfc\u81f4\u810f\u6570\u636e\u7684\u95ee\u9898\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> print<\/span>([<\/span>e<\/span>.<\/span>headline<\/span> for<\/span> e<\/span> in<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>all<\/span>()])<\/span>\r\n>>><\/span> print<\/span>([<\/span>e<\/span>.<\/span>pub_date<\/span> for<\/span> e<\/span> in<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>all<\/span>()])<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u4e3a\u4e86\u907f\u514d\u4e0a\u9762\u7684\u95ee\u9898\uff0c\u597d\u7684\u4f7f\u7528\u65b9\u5f0f\u5982\u4e0b\uff0c\u8fd9\u53ea\u4ea7\u751f\u4e00\u6b21\u5b9e\u9645\u7684\u67e5\u8be2\u64cd\u4f5c\uff0c\u5e76\u4e14\u4fdd\u6301\u4e86\u6570\u636e\u7684\u4e00\u81f4\u6027\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> queryset<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>all<\/span>()<\/span>\r\n>>><\/span> print<\/span>([<\/span>p<\/span>.<\/span>headline<\/span> for<\/span> p<\/span> in<\/span> queryset<\/span>])<\/span> # \u63d0\u4ea4\u67e5\u8be2<\/span>\r\n>>><\/span> print<\/span>([<\/span>p<\/span>.<\/span>pub_date<\/span> for<\/span> p<\/span> in<\/span> queryset<\/span>])<\/span> # \u91cd\u7528\u67e5\u8be2\u7f13\u5b58<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u4f55\u65f6\u4e0d\u4f1a\u88ab\u7f13\u5b58<\/span><\/p>\n
                                                                    \u6709\u4e00\u4e9b\u64cd\u4f5c\u4e0d\u4f1a\u7f13\u5b58QuerySet\uff0c\u4f8b\u5982\u5207\u7247\u548c\u7d22\u5f15\u3002\u8fd9\u5c31\u5bfc\u81f4\u8fd9\u4e9b\u64cd\u4f5c\u6ca1\u6709\u7f13\u5b58\u53ef\u7528\uff0c\u6bcf\u6b21\u90fd\u4f1a\u6267\u884c\u5b9e\u9645\u7684\u6570\u636e\u5e93\u67e5\u8be2\u64cd\u4f5c\u3002\u4f8b\u5982\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> queryset<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>all<\/span>()<\/span>\r\n>>><\/span> print<\/span>(<\/span>queryset<\/span>[<\/span>5<\/span>])<\/span> # \u67e5\u8be2\u6570\u636e\u5e93<\/span>\r\n>>><\/span> print<\/span>(<\/span>queryset<\/span>[<\/span>5<\/span>])<\/span> # \u518d\u6b21\u67e5\u8be2\u6570\u636e\u5e93<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u4f46\u662f\uff0c\u5982\u679c\u5df2\u7ecf\u904d\u5386\u8fc7\u6574\u4e2aQuerySet\uff0c\u90a3\u4e48\u5c31\u76f8\u5f53\u4e8e\u7f13\u5b58\u8fc7\uff0c\u540e\u7eed\u7684\u64cd\u4f5c\u5219\u4f1a\u4f7f\u7528\u7f13\u5b58\uff0c\u4f8b\u5982\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> queryset<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>all<\/span>()<\/span>\r\n>>><\/span> [<\/span>entry<\/span> for<\/span> entry<\/span> in<\/span> queryset<\/span>]<\/span> # \u67e5\u8be2\u6570\u636e\u5e93<\/span>\r\n>>><\/span> print<\/span>(<\/span>queryset<\/span>[<\/span>5<\/span>])<\/span> # \u4f7f\u7528\u7f13\u5b58<\/span>\r\n>>><\/span> print<\/span>(<\/span>queryset<\/span>[<\/span>5<\/span>])<\/span> # \u4f7f\u7528\u7f13\u5b58<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u4e0b\u9762\u7684\u8fd9\u4e9b\u64cd\u4f5c\u90fd\u5c06\u904d\u5386QuerySet\u5e76\u5efa\u7acb\u7f13\u5b58\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> [<\/span>entry<\/span> for<\/span> entry<\/span> in<\/span> queryset<\/span>]<\/span>\r\n>>><\/span> bool<\/span>(<\/span>queryset<\/span>)<\/span>\r\n>>><\/span> entry<\/span> in<\/span> queryset<\/span>\r\n>>><\/span> list<\/span>(<\/span>queryset<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u6ce8\u610f\uff1a\u7b80\u5355\u7684\u6253\u5370QuerySet\u5e76\u4e0d\u4f1a\u5efa\u7acb\u7f13\u5b58\uff0c\u56e0\u4e3a__repr__()<\/code>\u8c03\u7528\u53ea\u8fd4\u56de\u5168\u90e8\u67e5\u8be2\u96c6\u7684\u4e00\u4e2a\u5207\u7247\u3002<\/p>\n
                                                                    \u56db\u3001\u67e5\u8be2\u00a0JSONField<\/code><\/h1>\n
                                                                    Django3.1\u65b0\u589e\u4e86\u4e00\u79cd\u5b57\u6bb5\u7c7b\u578b\uff0c\u4e5f\u5c31\u662fJSONField \u3002<\/p>\n
                                                                    \u6ce8\u610f\uff1aSQLite3\u6570\u636e\u5e93\u4e0d\u652f\u6301JSONField\u5b57\u6bb5\u7c7b\u578b\u3002<\/p>\n
                                                                    JSONField \u91cc\u7684\u67e5\u627e\u5b9e\u73b0\u548c\u5176\u5b83\u5b57\u6bb5\u7c7b\u578b\u4e0d\u592a\u4e00\u6837\uff0c\u4e3b\u8981\u56e0\u4e3a\u5b58\u5728key\u8f6c\u6362\u3002\u4e3a\u4e86\u6f14\u793a\uff0c\u6211\u4eec\u5c06\u4f7f\u7528\u4e0b\u9762\u8fd9\u4e2a\u4f8b\u5b50\uff1a<\/p>\n
                                                                    \n
                                                                    from<\/span> django.db<\/span> import<\/span> models<\/span>\r\n\r\nclass<\/span> Dog<\/span>(<\/span>models<\/span>.<\/span>Model<\/span>):<\/span>\r\n    name<\/span> =<\/span> models<\/span>.<\/span>CharField<\/span>(<\/span>max_length<\/span>=<\/span>200<\/span>)<\/span>\r\n    data<\/span> =<\/span> models<\/span>.<\/span>JSONField<\/span>(<\/span>null<\/span>=<\/span>True<\/span>)<\/span>\r\n\r\n    def<\/span> __str__<\/span>(<\/span>self<\/span>):<\/span>\r\n        return<\/span> self<\/span>.<\/span>name<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u4fdd\u5b58\u548c\u67e5\u8be2 None \u503c<\/h2>\n
                                                                    \u56e0\u4e3aJSON\u3001Python\u548cSQL\u4e09\u8005\u5728\u7a7a\u503c\u4e0a\u7684\u5b9a\u4e49\u4e0d\u592a\u4e00\u6837\uff0c\u6240\u4ee5\u9700\u8981\u8c28\u614e\u5904\u7406\u3002<\/p>\n
                                                                    \u4e0e\u5176\u4ed6\u5b57\u6bb5\u4e00\u6837\uff0c\u5f53\u00a0None<\/code>\u00a0\u4f5c\u4e3a\u5b57\u6bb5\u503c\u6765\u4fdd\u5b58\u65f6\uff0c\u5c06\u50cf SQL \u7684 NULL \u503c\u4e00\u6837\u4fdd\u5b58\u3002\u867d\u7136\u4e0d\u5efa\u8bae\u8fd9\u6837\u505a\uff0c\u4f46\u53ef\u4ee5\u4f7f\u7528\u00a0Value('null')<\/code>\u00a0\u6765\u5b58\u50a8 JSON \u7684 null \u503c\u3002<\/p>\n
                                                                    \u65e0\u8bba\u5b58\u50a8\u54ea\u4e2a\u503c\uff0c\u5f53\u4ece\u6570\u636e\u5e93\u4e2d\u68c0\u7d22\u65f6\uff0cPython\u8868\u793aJSON\u7684\u7a7a\u503c\u548c SQL \u91cc\u7684 NULL \u4e00\u6837\uff0c\u90fd\u662f None \u3002\u56e0\u6b64\uff0c\u5f88\u96be\u533a\u5206\u5b83\u4eec\u3002<\/p>\n
                                                                    \u8fd9\u53ea\u9002\u7528\u4e8e None \u503c\u4f5c\u4e3a\u5b57\u6bb5\u7684\u9876\u7ea7\u503c\u3002\u5982\u679c None \u88ab\u4fdd\u5b58\u5728\u5217\u8868\u6216\u5b57\u5178\u4e2d\uff0c\u5b83\u5c06\u59cb\u7ec8\u88ab\u89e3\u91ca\u4e3aJSON\u7684 null \u503c\u3002<\/p>\n
                                                                    \u5f53\u67e5\u8be2\u65f6\uff0cNone \u503c\u5c06\u4e00\u76f4\u88ab\u89e3\u91ca\u4e3aJSON\u7684null<\/code>\u3002\u8981\u67e5\u8be2SQL\u7684NULL<\/code>\uff0c\u8bf7\u4f7f\u7528\u00a0isnull<\/code>\u53c2\u6570\u3002<\/p>\n
                                                                    \u8bf7\u4ed4\u7ec6\u63e3\u6469\u4e0b\u9762\u7684\u4f8b\u5b50\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>'Max'<\/span>,<\/span> data<\/span>=<\/span>None<\/span>)<\/span>  # SQL NULL.<\/span>\r\n<<\/span>Dog<\/span>:<\/span> Max<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>'Archie'<\/span>,<\/span> data<\/span>=<\/span>Value<\/span>(<\/span>'null'<\/span>))<\/span>  # JSON null.<\/span>\r\n<<\/span>Dog<\/span>:<\/span> Archie<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>data<\/span>=<\/span>None<\/span>)<\/span>\r\n<<\/span>QuerySet<\/span> [<\/span><<\/span>Dog<\/span>:<\/span> Archie<\/span>><\/span>]<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>data<\/span>=<\/span>Value<\/span>(<\/span>'null'<\/span>))<\/span>\r\n<<\/span>QuerySet<\/span> [<\/span><<\/span>Dog<\/span>:<\/span> Archie<\/span>><\/span>]<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>data__isnull<\/span>=<\/span>True<\/span>)<\/span>\r\n<<\/span>QuerySet<\/span> [<\/span><<\/span>Dog<\/span>:<\/span> Max<\/span>><\/span>]<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>data__isnull<\/span>=<\/span>False<\/span>)<\/span>\r\n<<\/span>QuerySet<\/span> [<\/span><<\/span>Dog<\/span>:<\/span> Archie<\/span>><\/span>]<\/span>><\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u9664\u975e\u4f60\u786e\u5b9a\u8981\u4f7f\u7528SQL \u7684\u00a0NULL<\/code>\u00a0\u503c\uff0c\u5426\u5219\u8bf7\u8003\u8651\u8bbe\u7f6e\u00a0null=False<\/code>\u00a0\u5e76\u4e3a\u7a7a\u503c\u63d0\u4f9b\u5408\u9002\u7684\u9ed8\u8ba4\u503c\uff0c\u4f8b\u5982\u00a0default=dict()<\/code>\u00a0\u3002<\/p>\n
                                                                    \u6ce8\u610f\uff1a\u4fdd\u5b58JSON\u7684\u00a0null<\/code>\u00a0\u503c\u4e0d\u8fdd\u53cdDjango\u7684\u00a0null=False<\/code>\u00a0\u3002<\/p>\n
                                                                    Key, index, \u548c\u8def\u5f84\u8f6c\u6362<\/h2>\n
                                                                    \u4e3a\u4e86\u67e5\u8be2\u7ed9\u5b9a\u7684\u5b57\u5178\u952e\uff0c\u8bf7\u5c06\u8be5\u952e\u4f5c\u4e3a\u67e5\u8be2\u540d\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>'Rufus'<\/span>,<\/span> data<\/span>=<\/span>{<\/span>\r\n...<\/span>     'breed'<\/span>:<\/span> 'labrador'<\/span>,<\/span>\r\n...<\/span>     'owner'<\/span>:<\/span> {<\/span>\r\n...<\/span>         'name'<\/span>:<\/span> 'Bob'<\/span>,<\/span>\r\n...<\/span>         'other_pets'<\/span>:<\/span> [{<\/span>\r\n...<\/span>             'name'<\/span>:<\/span> 'Fishy'<\/span>,<\/span>\r\n...<\/span>         }],<\/span>\r\n...<\/span>     },<\/span>\r\n...<\/span> })<\/span>\r\n<<\/span>Dog<\/span>:<\/span> Rufus<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>'Meg'<\/span>,<\/span> data<\/span>=<\/span>{<\/span>'breed'<\/span>:<\/span> 'collie'<\/span>,<\/span> 'owner'<\/span>:<\/span> None<\/span>})<\/span>\r\n<<\/span>Dog<\/span>:<\/span> Meg<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>data__breed<\/span>=<\/span>'collie'<\/span>)<\/span>\r\n<<\/span>QuerySet<\/span> [<\/span><<\/span>Dog<\/span>:<\/span> Meg<\/span>><\/span>]<\/span>><\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u53ef\u4ee5\u5c06\u591a\u4e2a\u952e\u7528\u53cc\u4e0b\u5212\u7ebf\u94fe\u63a5\u8d77\u6765\u5f62\u6210\u4e00\u4e2a\u8def\u5f84\u67e5\u8be2\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>data__owner__name<\/span>=<\/span>'Bob'<\/span>)<\/span>\r\n<<\/span>QuerySet<\/span> [<\/span><<\/span>Dog<\/span>:<\/span> Rufus<\/span>><\/span>]<\/span>><\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u5982\u679c\u952e\u662f\u4e2a\u6574\u6570\uff0c\u90a3\u4e48\u5b83\u5c06\u5728\u5217\u8868\u4e2d\u88ab\u89e3\u91ca\u6210\u4e00\u4e2a\u7d22\u5f15\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>data__owner__other_pets__0__name<\/span>=<\/span>'Fishy'<\/span>)<\/span>\r\n<<\/span>QuerySet<\/span> [<\/span><<\/span>Dog<\/span>:<\/span> Rufus<\/span>><\/span>]<\/span>><\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u5982\u679c\u8981\u67e5\u8be2\u7684\u952e\u4e0e\u53e6\u4e00\u4e2a\u67e5\u8be2\u7684\u952e\u540d\u51b2\u7a81\uff0c\u8bf7\u6539\u7528\u00a0contains<\/code>\u00a0\u6765\u67e5\u8be2\u3002<\/p>\n
                                                                    \u5982\u679c\u67e5\u8be2\u65f6\u7f3a\u5c11\u952e\u540d\uff0c\u8bf7\u4f7f\u7528\u00a0isnull<\/code>\u00a0\u67e5\u8be2\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>'Shep'<\/span>,<\/span> data<\/span>=<\/span>{<\/span>'breed'<\/span>:<\/span> 'collie'<\/span>})<\/span>\r\n<<\/span>Dog<\/span>:<\/span> Shep<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>data__owner__isnull<\/span>=<\/span>True<\/span>)<\/span>\r\n<<\/span>QuerySet<\/span> [<\/span><<\/span>Dog<\/span>:<\/span> Shep<\/span>><\/span>]<\/span>><\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u4e0a\u9762\u7ed9\u51fa\u7684\u4f8b\u5b50\u9690\u5f0f\u5730\u4f7f\u7528\u4e86exact \u67e5\u627e\u3002Key\u3001\u7d22\u5f15\u548c\u8def\u5f84\u8f6c\u6362\u4e5f\u53ef\u4ee5\u7528\uff1aicontains, endswith, iendswith, iexact, regex, iregex, startswith, istartswith, lt, lte, gt, gte\u7b49\u67e5\u8be2\u624b\u6bb5\u3002<\/p>\n
                                                                    \u5305\u542b\u4e0e\u952e\u67e5\u627e<\/h2>\n
                                                                    contains<\/h3>\n
                                                                    JSONField<\/code>\u00a0\u4e0a\u7684\u00a0contains<\/code>\u00a0\u67e5\u627e\u903b\u8f91\u88ab\u91cd\u5199\u4e86\u3002\u8fd4\u56de\u7684\u5bf9\u8c61\u662f\u90a3\u4e9b\u7ed9\u5b9a\u7684\u952e\u503c\u5bf9\u90fd\u5305\u542b\u5728\u9876\u7ea7\u5b57\u6bb5\u4e2d\u7684\u5bf9\u8c61\u3002\u4f8b\u5982\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>'Rufus'<\/span>,<\/span> data<\/span>=<\/span>{<\/span>'breed'<\/span>:<\/span> 'labrador'<\/span>,<\/span> 'owner'<\/span>:<\/span> 'Bob'<\/span>})<\/span>\r\n<<\/span>Dog<\/span>:<\/span> Rufus<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>'Meg'<\/span>,<\/span> data<\/span>=<\/span>{<\/span>'breed'<\/span>:<\/span> 'collie'<\/span>,<\/span> 'owner'<\/span>:<\/span> 'Bob'<\/span>})<\/span>\r\n<<\/span>Dog<\/span>:<\/span> Meg<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>'Fred'<\/span>,<\/span> data<\/span>=<\/span>{})<\/span>\r\n<<\/span>Dog<\/span>:<\/span> Fred<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>data__contains<\/span>=<\/span>{<\/span>'owner'<\/span>:<\/span> 'Bob'<\/span>})<\/span>\r\n<<\/span>QuerySet<\/span> [<\/span><<\/span>Dog<\/span>:<\/span> Rufus<\/span>><\/span>,<\/span> <<\/span>Dog<\/span>:<\/span> Meg<\/span>><\/span>]<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>data__contains<\/span>=<\/span>{<\/span>'breed'<\/span>:<\/span> 'collie'<\/span>})<\/span>\r\n<<\/span>QuerySet<\/span> [<\/span><<\/span>Dog<\/span>:<\/span> Meg<\/span>><\/span>]<\/span>><\/span>\r\n<\/pre>\n<\/div>\n
                                                                    Oracle \u548c SQLite \u5728\u8fd9\u91cc\u4e0d\u652f\u6301\u00a0contains<\/code>\u00a0\u3002<\/p>\n
                                                                    contained_by<\/h3>\n
                                                                    \u5c06\u53c2\u6570\u503c\u5b9a\u4e49\u4e3a\u96c6\u5408A\uff0c\u6bcf\u4e2a\u5b9e\u4f8b\u7684\u503c\u5b9a\u4e49\u4e3a\u96c6\u5408B\uff0c\u5982\u679cB\u662fA\u7684\u5b50\u96c6\uff0c\u90a3\u4e48\u8fd9\u4e2a\u5b9e\u4f8b\u5c06\u88ab\u9009\u4e2d\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>'Rufus'<\/span>,<\/span> data<\/span>=<\/span>{<\/span>'breed'<\/span>:<\/span> 'labrador'<\/span>,<\/span> 'owner'<\/span>:<\/span> 'Bob'<\/span>})<\/span>\r\n<<\/span>Dog<\/span>:<\/span> Rufus<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>'Meg'<\/span>,<\/span> data<\/span>=<\/span>{<\/span>'breed'<\/span>:<\/span> 'collie'<\/span>,<\/span> 'owner'<\/span>:<\/span> 'Bob'<\/span>})<\/span>\r\n<<\/span>Dog<\/span>:<\/span> Meg<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>'Fred'<\/span>,<\/span> data<\/span>=<\/span>{})<\/span>\r\n<<\/span>Dog<\/span>:<\/span> Fred<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>data__contained_by<\/span>=<\/span>{<\/span>'breed'<\/span>:<\/span> 'collie'<\/span>,<\/span> 'owner'<\/span>:<\/span> 'Bob'<\/span>})<\/span>\r\n<<\/span>QuerySet<\/span> [<\/span><<\/span>Dog<\/span>:<\/span> Meg<\/span>><\/span>,<\/span> <<\/span>Dog<\/span>:<\/span> Fred<\/span>><\/span>]<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>data__contained_by<\/span>=<\/span>{<\/span>'breed'<\/span>:<\/span> 'collie'<\/span>})<\/span>\r\n<<\/span>QuerySet<\/span> [<\/span><<\/span>Dog<\/span>:<\/span> Fred<\/span>><\/span>]<\/span>><\/span>\r\n<\/pre>\n<\/div>\n
                                                                    Oracle \u548c SQLite\u4e0d\u652f\u6301contained_by<\/code>\u3002<\/p>\n
                                                                    has_key<\/h3>\n
                                                                    \u901a\u8fc7\u952e\u8fc7\u6ee4\u5bf9\u8c61\uff0c\u5339\u914d\u7684\u952e\u5fc5\u987b\u4f4d\u4e8e\u5d4c\u5957\u7684\u6700\u9876\u5c42\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>'Rufus'<\/span>,<\/span> data<\/span>=<\/span>{<\/span>'breed'<\/span>:<\/span> 'labrador'<\/span>})<\/span>\r\n<<\/span>Dog<\/span>:<\/span> Rufus<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>'Meg'<\/span>,<\/span> data<\/span>=<\/span>{<\/span>'breed'<\/span>:<\/span> 'collie'<\/span>,<\/span> 'owner'<\/span>:<\/span> 'Bob'<\/span>})<\/span>\r\n<<\/span>Dog<\/span>:<\/span> Meg<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>data__has_key<\/span>=<\/span>'owner'<\/span>)<\/span>\r\n<<\/span>QuerySet<\/span> [<\/span><<\/span>Dog<\/span>:<\/span> Meg<\/span>><\/span>]<\/span>><\/span>\r\n<\/pre>\n<\/div>\n
                                                                    has_keys<\/h3>\n
                                                                    \u8fd4\u56de\u540c\u65f6\u5177\u5907\u6307\u5b9a\u7684\u591a\u4e2a\u952e\u7684\u5bf9\u8c61\uff0c\u8fd9\u4e9b\u952e\u5fc5\u987b\u4f4d\u4e8e\u6700\u9876\u5c42\u3002:<\/p>\n
                                                                    \n
                                                                    >>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>'Rufus'<\/span>,<\/span> data<\/span>=<\/span>{<\/span>'breed'<\/span>:<\/span> 'labrador'<\/span>})<\/span>\r\n<<\/span>Dog<\/span>:<\/span> Rufus<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>'Meg'<\/span>,<\/span> data<\/span>=<\/span>{<\/span>'breed'<\/span>:<\/span> 'collie'<\/span>,<\/span> 'owner'<\/span>:<\/span> 'Bob'<\/span>})<\/span>\r\n<<\/span>Dog<\/span>:<\/span> Meg<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>data__has_keys<\/span>=<\/span>[<\/span>'breed'<\/span>,<\/span> 'owner'<\/span>])<\/span>\r\n<<\/span>QuerySet<\/span> [<\/span><<\/span>Dog<\/span>:<\/span> Meg<\/span>><\/span>]<\/span>><\/span>\r\n<\/pre>\n<\/div>\n
                                                                    has_any_keys<\/h3>\n
                                                                    \u53ea\u8981\u5177\u5907\u6307\u5b9a\u952e\u5217\u8868\u4e2d\u7684\u4efb\u4f55\u4e00\u4e2a\u952e\uff0c\u8fd9\u4e2a\u5bf9\u8c61\u5c31\u4f1a\u88ab\u8fd4\u56de\u3002\u8fd9\u4e9b\u952e\u5fc5\u987b\u4f4d\u4e8e\u6700\u9876\u5c42\u3002<\/p>\n
                                                                    \n
                                                                    >>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>'Rufus'<\/span>,<\/span> data<\/span>=<\/span>{<\/span>'breed'<\/span>:<\/span> 'labrador'<\/span>})<\/span>\r\n<<\/span>Dog<\/span>:<\/span> Rufus<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>create<\/span>(<\/span>name<\/span>=<\/span>'Meg'<\/span>,<\/span> data<\/span>=<\/span>{<\/span>'owner'<\/span>:<\/span> 'Bob'<\/span>})<\/span>\r\n<<\/span>Dog<\/span>:<\/span> Meg<\/span>><\/span>\r\n>>><\/span> Dog<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>data__has_any_keys<\/span>=<\/span>[<\/span>'owner'<\/span>,<\/span> 'breed'<\/span>])<\/span>\r\n<<\/span>QuerySet<\/span> [<\/span><<\/span>Dog<\/span>:<\/span> Rufus<\/span>><\/span>,<\/span> <<\/span>Dog<\/span>:<\/span> Meg<\/span>><\/span>]<\/span>><\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u8bf7\u601d\u8003\u4e00\u4e2a\u95ee\u9898\uff0c\u80fd\u4e0d\u80fd\u5bf9JSONField\u4e2ddata\u7684\u4e8c\u7ea7\u3001\u4e09\u7ea7\u6216\u66f4\u6df1\u5165\u5c42\u6b21\u8fdb\u884c\u952e\u5339\u914d\u67e5\u8be2\u5462\uff1f<\/p>\n
                                                                    \u5982\u679c\u80fd\uff0c\u600e\u4e48\u505a\uff1f\u8bd5\u8bd5\u5c31\u77e5\u9053\u4e86\uff01<\/p>\n
                                                                    \u4e94\u3001Q\u5bf9\u8c61<\/h1>\n
                                                                    \u666e\u901afilter\u67e5\u8be2\u91cc\u7684\u6761\u4ef6\u90fd\u662f\u201cand\u201d\u903b\u8f91\uff0c\u5982\u679c\u4f60\u60f3\u5b9e\u73b0\u201cor\u201d\u903b\u8f91\u600e\u4e48\u529e\uff1f\u7528Q\u67e5\u8be2\uff01<\/p>\n
                                                                    Q\u6765\u81eadjango.db.models.Q<\/code>\uff0c\u7528\u4e8e\u5c01\u88c5\u5173\u952e\u5b57\u53c2\u6570\u7684\u96c6\u5408\uff0c\u53ef\u4ee5\u4f5c\u4e3a\u5173\u952e\u5b57\u53c2\u6570\u7528\u4e8efilter\u3001exclude\u548cget\u7b49\u51fd\u6570\u3002 \u4f8b\u5982\uff1a<\/p>\n
                                                                    \n
                                                                    from<\/span> django.db.models<\/span> import<\/span> Q<\/span>\r\nQ<\/span>(<\/span>question__startswith<\/span>=<\/span>'What'<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u53ef\u4ee5\u4f7f\u7528&<\/code>\u6216\u8005|<\/code>\u6216~<\/code>\u6765\u7ec4\u5408Q\u5bf9\u8c61\uff0c\u5206\u522b\u8868\u793a\u4e0e\u3001\u6216\u3001\u975e\u903b\u8f91\u3002\u5b83\u5c06\u8fd4\u56de\u4e00\u4e2a\u65b0\u7684Q\u5bf9\u8c61\u3002<\/p>\n
                                                                    \n
                                                                    Q<\/span>(<\/span>question__startswith<\/span>=<\/span>'Who'<\/span>)<\/span>|<\/span>Q<\/span>(<\/span>question__startswith<\/span>=<\/span>'What'<\/span>)<\/span>\r\n# \u8fd9\u76f8\u5f53\u4e8e\uff1a<\/span>\r\nWHERE<\/span> question<\/span> LIKE<\/span> 'Who%'<\/span> OR<\/span> question<\/span> LIKE<\/span> 'What%'<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u66f4\u591a\u7684\u4f8b\u5b50\uff1a<\/p>\n
                                                                    \n
                                                                    Q<\/span>(<\/span>question__startswith<\/span>=<\/span>'Who'<\/span>)<\/span> |<\/span> ~<\/span>Q<\/span>(<\/span>pub_date__year<\/span>=<\/span>2005<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u4f60\u4e5f\u53ef\u4ee5\u8fd9\u4e48\u4f7f\u7528\uff0c\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u4ee5\u9017\u53f7\u5206\u9694\u7684\u90fd\u8868\u793aAND\u5173\u7cfb\uff1a<\/p>\n
                                                                    \n
                                                                    Poll<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>\r\nQ<\/span>(<\/span>question__startswith<\/span>=<\/span>'Who'<\/span>),<\/span>\r\nQ<\/span>(<\/span>pub_date<\/span>=<\/span>date<\/span>(<\/span>2005<\/span>,<\/span> 5<\/span>,<\/span> 2<\/span>))<\/span> |<\/span> Q<\/span>(<\/span>pub_date<\/span>=<\/span>date<\/span>(<\/span>2005<\/span>,<\/span> 5<\/span>,<\/span> 6<\/span>))<\/span>\r\n)<\/span>\r\n# \u5b83\u76f8\u5f53\u4e8e<\/span>\r\n# SELECT * from polls WHERE question LIKE 'Who%'<\/span>\r\nAND<\/span> (<\/span>pub_date<\/span> =<\/span> '2005-05-02'<\/span> OR<\/span> pub_date<\/span> =<\/span> '2005-05-06'<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u5f53\u5173\u952e\u5b57\u53c2\u6570\u548cQ\u5bf9\u8c61\u7ec4\u5408\u4f7f\u7528\u65f6\uff0cQ\u5bf9\u8c61\u5fc5\u987b\u653e\u5728\u524d\u9762\uff0c\u5982\u4e0b\u4f8b\u5b50\uff1a<\/p>\n
                                                                    \n
                                                                    Poll<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>\r\nQ<\/span>(<\/span>pub_date<\/span>=<\/span>date<\/span>(<\/span>2005<\/span>,<\/span> 5<\/span>,<\/span> 2<\/span>))<\/span> |<\/span> Q<\/span>(<\/span>pub_date<\/span>=<\/span>date<\/span>(<\/span>2005<\/span>,<\/span> 5<\/span>,<\/span> 6<\/span>)),<\/span> question__startswith<\/span>=<\/span>'Who'<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u516d\u3001\u6bd4\u8f83\u5bf9\u8c61<\/h1>\n
                                                                    \u8981\u6bd4\u8f83\u4e24\u4e2a\u6a21\u578b\u5b9e\u4f8b\uff0c\u53ea\u9700\u8981\u4f7f\u7528python\u63d0\u4f9b\u7684\u53cc\u7b49\u53f7\u6bd4\u8f83\u7b26\u5c31\u53ef\u4ee5\u4e86\u3002\u5728\u540e\u53f0\uff0c\u5176\u5b9e\u6bd4\u8f83\u7684\u662f\u4e24\u4e2a\u5b9e\u4f8b\u7684\u4e3b\u952e\u7684\u503c\u3002\u4e0b\u9762\u4e24\u79cd\u65b9\u6cd5\u662f\u7b49\u540c\u7684\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> some_entry<\/span> ==<\/span> other_entry<\/span>\r\n>>><\/span> some_entry<\/span>.<\/span>id<\/span> ==<\/span> other_entry<\/span>.<\/span>id<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u5982\u679c\u6a21\u578b\u7684\u4e3b\u952e\u4e0d\u53eb\u505a\u201cid\u201d\u4e5f\u6ca1\u5173\u7cfb\uff0c\u540e\u53f0\u603b\u662f\u4f1a\u4f7f\u7528\u6b63\u786e\u7684\u4e3b\u952e\u540d\u5b57\u8fdb\u884c\u6bd4\u8f83\uff0c\u4f8b\u5982\uff0c\u5982\u679c\u4e00\u4e2a\u6a21\u578b\u7684\u4e3b\u952e\u7684\u540d\u5b57\u662f\u201cname\u201d\uff0c\u90a3\u4e48\u4e0b\u9762\u662f\u76f8\u7b49\u7684\uff1a<\/p>\n
                                                                    \n
                                                                    >>><\/span> some_obj<\/span> ==<\/span> other_obj<\/span>\r\n>>><\/span> some_obj<\/span>.<\/span>name<\/span> ==<\/span> other_obj<\/span>.<\/span>name<\/span>\r\n<\/pre>\n<\/div>\n
                                                                    \u8fd9\u5176\u5b9e\u662fDjango\u5728\u5185\u90e8\u4e3amodels.Model<\/code>\u5b9e\u73b0\u4e86__eq__()<\/code>\u9b54\u6cd5\u65b9\u6cd5\uff0c\u7528\u6765\u5bf9\u6a21\u578b\u5b9e\u4f8b\u8fdb\u884c\u662f\u5426\u76f8\u7b49\u7684\u5e03\u5c14\u5224\u65ad\u3002<\/p>\n
                                                                    \u5224\u65ad\u57fa\u4e8e\u4e0b\u9762\u7684\u903b\u8f91\uff1a<\/p>\n
                                                                      \n
                                                                    • \u540c\u4e00\u6a21\u578b\u4e0b\uff0c\u4e3b\u952e\u76f8\u7b49\u5219\u5b9e\u4f8b\u76f8\u7b49<\/li>\n
                                                                    • \u4e3b\u952e\u4e3aNone\u65f6\uff0c\u548c\u4efb\u4f55\u5b9e\u4f8b\u90fd\u4e0d\u76f8\u7b49<\/li>\n
                                                                    • \u5b9e\u4f8b\u7b49\u4e8e\u81ea\u5df1\u672c\u8eab<\/li>\n
                                                                    • \u4ee3\u7406\u6a21\u578b\u7684\u5b9e\u4f8b\u7b49\u4e8e\u76f8\u540c\u4e3b\u952e\u7684\u7236\u7c7b\u5b9e\u4f8b<\/li>\n
                                                                    • \u591a\u8868\u7ee7\u627f\u65f6\uff0c\u54ea\u6015\u4e3b\u952e\u503c\u76f8\u7b49\uff0c\u5b9e\u4f8b\u4e5f\u4e0d\u76f8\u7b49<\/li>\n<\/ul>\n
                                                                      \u53c2\u8003\u4e0b\u9762\u7684\u4f8b\u5b50\uff1a<\/p>\n
                                                                      \n
                                                                      from<\/span> django.db<\/span> import<\/span> models<\/span>\r\n\r\nclass<\/span> MyModel<\/span>(<\/span>models<\/span>.<\/span>Model<\/span>):<\/span>\r\n    id<\/span> =<\/span> models<\/span>.<\/span>AutoField<\/span>(<\/span>primary_key<\/span>=<\/span>True<\/span>)<\/span>\r\n\r\nclass<\/span> MyProxyModel<\/span>(<\/span>MyModel<\/span>):<\/span>\r\n    class<\/span> Meta<\/span>:<\/span>\r\n        proxy<\/span> =<\/span> True<\/span>\r\n\r\nclass<\/span> MultitableInherited<\/span>(<\/span>MyModel<\/span>):<\/span>\r\n    pass<\/span>\r\n\r\n# \u4e3b\u952e\u5bf9\u6bd4<\/span>\r\nMyModel<\/span>(<\/span>id<\/span>=<\/span>1<\/span>)<\/span> ==<\/span> MyModel<\/span>(<\/span>id<\/span>=<\/span>1<\/span>)<\/span>\r\nMyModel<\/span>(<\/span>id<\/span>=<\/span>1<\/span>)<\/span> !=<\/span> MyModel<\/span>(<\/span>id<\/span>=<\/span>2<\/span>)<\/span>\r\n\r\n# \u4e3b\u952e\u4e3aNone<\/span>\r\nMyModel<\/span>(<\/span>id<\/span>=<\/span>None<\/span>)<\/span> !=<\/span> MyModel<\/span>(<\/span>id<\/span>=<\/span>None<\/span>)<\/span>\r\n\r\n# \u76f8\u540c\u7684\u5b9e\u4f8b<\/span>\r\ninstance<\/span> =<\/span> MyModel<\/span>(<\/span>id<\/span>=<\/span>None<\/span>)<\/span>\r\ninstance<\/span> ==<\/span> instance<\/span>\r\n\r\n# \u4ee3\u7406\u6a21\u578b\u548c\u7236\u7c7b<\/span>\r\nMyModel<\/span>(<\/span>id<\/span>=<\/span>1<\/span>)<\/span> ==<\/span> MyProxyModel<\/span>(<\/span>id<\/span>=<\/span>1<\/span>)<\/span>\r\n\r\n# \u591a\u8868\u7ee7\u627f<\/span>\r\nMyModel<\/span>(<\/span>id<\/span>=<\/span>1<\/span>)<\/span> !=<\/span> MultitableInherited<\/span>(<\/span>id<\/span>=<\/span>1<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                      \u4e03\u3001\u5220\u9664\u5bf9\u8c61<\/h1>\n
                                                                      \u5220\u9664\u5bf9\u8c61\u4f7f\u7528\u7684\u662f\u5bf9\u8c61\u7684delete()<\/code>\u65b9\u6cd5\u3002\u8be5\u65b9\u6cd5\u5c06\u8fd4\u56de\u88ab\u5220\u9664\u5bf9\u8c61\u7684\u603b\u6570\u91cf\u548c\u4e00\u4e2a\u5b57\u5178\uff0c\u5b57\u5178\u5305\u542b\u4e86\u6bcf\u79cd\u88ab\u5220\u9664\u5bf9\u8c61\u7684\u7c7b\u578b\u548c\u8be5\u7c7b\u578b\u7684\u6570\u91cf\u3002\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n
                                                                      \n
                                                                      >>><\/span> e<\/span>.<\/span>delete<\/span>()<\/span>\r\n(<\/span>1<\/span>,<\/span> {<\/span>'weblog.Entry'<\/span>:<\/span> 1<\/span>})<\/span>\r\n<\/pre>\n<\/div>\n
                                                                      \u4e5f\u53ef\u4ee5\u6279\u91cf\u5220\u9664\u3002\u6bcf\u4e2aQuerySet\u90fd\u6709\u4e00\u4e2adelete()\u65b9\u6cd5\uff0c\u5b83\u80fd\u5220\u9664\u8be5QuerySet\u7684\u6240\u6709\u6210\u5458\u3002\u4f8b\u5982\uff1a<\/p>\n
                                                                      \n
                                                                      >>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>pub_date__year<\/span>=<\/span>2020<\/span>)<\/span>.<\/span>delete<\/span>()<\/span>\r\n(<\/span>5<\/span>,<\/span> {<\/span>'webapp.Entry'<\/span>:<\/span> 5<\/span>})<\/span>\r\n<\/pre>\n<\/div>\n
                                                                      \u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u6709\u53ef\u80fd\u4e0d\u662f\u6bcf\u4e00\u4e2a\u5bf9\u8c61\u7684delete\u65b9\u6cd5\u90fd\u88ab\u6267\u884c\u3002\u5982\u679c\u4f60\u6539\u5199\u4e86delete\u65b9\u6cd5\uff0c\u4e3a\u4e86\u786e\u4fdd\u5bf9\u8c61\u88ab\u5220\u9664\uff0c\u4f60\u5fc5\u987b\u624b\u52a8\u8fed\u4ee3QuerySet\u8fdb\u884c\u9010\u4e00\u5220\u9664\u64cd\u4f5c\u3002<\/p>\n
                                                                      \u5f53Django\u5220\u9664\u4e00\u4e2a\u5bf9\u8c61\u65f6\uff0c\u5b83\u9ed8\u8ba4\u4f7f\u7528SQL\u7684ON DELETE CASCADE\u7ea6\u675f\uff0c\u4e5f\u5c31\u662f\u8bf4\uff0c\u4efb\u4f55\u6709\u5916\u952e\u6307\u5411\u8981\u5220\u9664\u5bf9\u8c61\u7684\u5bf9\u8c61\u5c06\u4e00\u8d77\u88ab\u5220\u9664\u3002\u4f8b\u5982\uff1a<\/p>\n
                                                                      \n
                                                                      b<\/span> =<\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>pk<\/span>=<\/span>1<\/span>)<\/span>\r\n# \u4e0b\u9762\u7684\u52a8\u4f5c\u5c06\u5220\u9664\u8be5\u6761Blog\u548c\u6240\u6709\u7684\u5b83\u5173\u8054\u7684Entry\u5bf9\u8c61<\/span>\r\nb<\/span>.<\/span>delete<\/span>()<\/span>\r\n<\/pre>\n<\/div>\n
                                                                      \u8fd9\u79cd\u7ea7\u8054\u7684\u884c\u4e3a\u53ef\u4ee5\u901a\u8fc7\u7684ForeignKey\u7684on_delete<\/code>\u53c2\u6570\u81ea\u5b9a\u4e49\u3002<\/p>\n
                                                                      \u6ce8\u610f\uff0cdelete()<\/code>\u662f\u552f\u4e00\u6ca1\u6709\u5728\u7ba1\u7406\u5668\u4e0a\u66b4\u9732\u51fa\u6765\u7684\u65b9\u6cd5\u3002\u8fd9\u662f\u523b\u610f\u8bbe\u8ba1\u7684\u4e00\u4e2a\u5b89\u5168\u673a\u5236\uff0c\u7528\u6765\u9632\u6b62\u4f60\u610f\u5916\u5730\u8bf7\u6c42\u7c7b\u4f3cEntry.objects.delete()<\/code>\u7684\u52a8\u4f5c\uff0c\u800c\u4e0d\u614e\u5220\u9664\u4e86\u6240\u6709\u7684\u6761\u76ee\u3002\u5982\u679c\u4f60\u786e\u5b9e\u60f3\u5220\u9664\u6240\u6709\u7684\u5bf9\u8c61\uff0c\u4f60\u5fc5\u987b\u660e\u786e\u5730\u8bf7\u6c42\u4e00\u4e2a\u5b8c\u5168\u7684\u67e5\u8be2\u96c6\uff0c\u50cf\u4e0b\u9762\u8fd9\u6837\uff1a<\/p>\n
                                                                      \n
                                                                      Entry<\/span>.<\/span>objects<\/span>.<\/span>all<\/span>()<\/span>.<\/span>delete<\/span>()<\/span>\r\n<\/pre>\n<\/div>\n
                                                                      \u5728\u591a\u8868\u7ee7\u627f\u65f6\uff0c\u5982\u679c\u4f60\u53ea\u60f3\u5220\u9664\u5b50\u7c7b\u7684\u5bf9\u8c61\uff0c\u800c\u4e0d\u60f3\u5220\u9664\u7236\u7c7b\u7684\u6570\u636e\uff0c\u53ef\u4ee5\u4f7f\u7528\u53c2\u6570keep_parents=True<\/code>\u3002<\/p>\n
                                                                      \u6ce8\u610f\uff1a\u6709\u4e9b\u5220\u9664\u6a21\u578b\u5b9e\u4f8b\u7684\u65b9\u6cd5\u4e0d\u4f1a\u89e6\u53d1delete()\u65b9\u6cd5\uff0c\u6bd4\u5982\u6279\u91cf\u5220\u9664\u548c\u7ea7\u8054\u5220\u9664\uff0c\u4e3a\u4e86\u786e\u4fdd\u4f60\u7684\u81ea\u5b9a\u4e49\u4ee3\u7801\u88ab\u6267\u884c\uff0c\u8bf7\u4f7f\u7528pre_delete<\/code>\u6216\u8005post_delete<\/code>\u4fe1\u53f7\u673a\u5236\u6765\u66ff\u4ee3delete\u65b9\u6cd5\u3002<\/p>\n
                                                                      \u516b\u3001\u590d\u5236\u6a21\u578b\u5b9e\u4f8b<\/h1>\n
                                                                      \u867d\u7136\u6ca1\u6709\u5185\u7f6e\u7684\u65b9\u6cd5\u7528\u4e8e\u590d\u5236\u6a21\u578b\u7684\u5b9e\u4f8b\uff0c\u4f46\u8fd8\u662f\u5f88\u5bb9\u6613\u521b\u5efa\u4e00\u4e2a\u65b0\u7684\u5b9e\u4f8b\u5e76\u5c06\u539f\u5b9e\u4f8b\u7684\u6240\u6709\u5b57\u6bb5\u90fd\u62f7\u8d1d\u8fc7\u6765\u3002\u6700\u7b80\u5355\u7684\u65b9\u6cd5\u662f\u5c06\u539f\u5b9e\u4f8b\u7684pk\u8bbe\u7f6e\u4e3aNone\uff0c\u8fd9\u4f1a\u521b\u5efa\u4e00\u4e2a\u65b0\u7684\u5b9e\u4f8bcopy\u3002\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n
                                                                      \n
                                                                      blog<\/span> =<\/span> Blog<\/span>(<\/span>name<\/span>=<\/span>'My blog'<\/span>,<\/span> tagline<\/span>=<\/span>'Blogging is easy'<\/span>)<\/span>\r\nblog<\/span>.<\/span>save<\/span>()<\/span> # blog.pk == 1<\/span>\r\n#<\/span>\r\nblog<\/span>.<\/span>pk<\/span> =<\/span> None<\/span>\r\nblog<\/span>.<\/span>save<\/span>()<\/span> # blog.pk == 2<\/span>\r\n<\/pre>\n<\/div>\n
                                                                      \u4f46\u662f\u5728\u7ee7\u627f\u7236\u7c7b\u7684\u65f6\u5019\uff0c\u60c5\u51b5\u4f1a\u53d8\u5f97\u590d\u6742\uff0c\u5982\u679c\u6709\u4e0b\u9762\u4e00\u4e2aBlog\u7684\u5b50\u7c7b\uff1a<\/p>\n
                                                                      \n
                                                                      class<\/span> ThemeBlog<\/span>(<\/span>Blog<\/span>):<\/span>\r\n    theme<\/span> =<\/span> models<\/span>.<\/span>CharField<\/span>(<\/span>max_length<\/span>=<\/span>200<\/span>)<\/span>\r\n\r\ndjango_blog<\/span> =<\/span> ThemeBlog<\/span>(<\/span>name<\/span>=<\/span>'Django'<\/span>,<\/span> tagline<\/span>=<\/span>'Django is easy'<\/span>,<\/span> theme<\/span>=<\/span>'python'<\/span>)<\/span>\r\ndjango_blog<\/span>.<\/span>save<\/span>()<\/span> # django_blog.pk == 3<\/span>\r\n<\/pre>\n<\/div>\n
                                                                      \u57fa\u4e8e\u7ee7\u627f\u7684\u5de5\u4f5c\u673a\u5236\uff0c\u4f60\u5fc5\u987b\u540c\u65f6\u5c06pk\u548cid\u8bbe\u4e3aNone\uff1a<\/p>\n
                                                                      \n
                                                                      django_blog<\/span>.<\/span>pk<\/span> =<\/span> None<\/span>\r\ndjango_blog<\/span>.<\/span>id<\/span> =<\/span> None<\/span>\r\ndjango_blog<\/span>.<\/span>save<\/span>()<\/span> # django_blog.pk == 4<\/span>\r\n<\/pre>\n<\/div>\n
                                                                      \u5bf9\u4e8e\u5916\u952e\u548c\u591a\u5bf9\u591a\u5173\u7cfb\uff0c\u66f4\u9700\u8981\u8fdb\u4e00\u6b65\u5904\u7406\u3002\u4f8b\u5982\uff0cEntry\u6709\u4e00\u4e2aManyToManyField\u5230Author\u3002 \u590d\u5236\u6761\u76ee\u540e\uff0c\u60a8\u5fc5\u987b\u4e3a\u65b0\u6761\u76ee\u8bbe\u7f6e\u591a\u5bf9\u591a\u5173\u7cfb\uff0c\u50cf\u4e0b\u9762\u8fd9\u6837\uff1a<\/p>\n
                                                                      \n
                                                                      entry<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>all<\/span>()[<\/span>0<\/span>]<\/span> # some previous entry<\/span>\r\nold_authors<\/span> =<\/span> entry<\/span>.<\/span>authors<\/span>.<\/span>all<\/span>()<\/span>\r\nentry<\/span>.<\/span>pk<\/span> =<\/span> None<\/span>\r\nentry<\/span>.<\/span>save<\/span>()<\/span>\r\nentry<\/span>.<\/span>authors<\/span>.<\/span>set<\/span>(<\/span>old_authors<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                      \u5bf9\u4e8eOneToOneField\uff0c\u8fd8\u8981\u590d\u5236\u76f8\u5173\u5bf9\u8c61\u5e76\u5c06\u5176\u5206\u914d\u7ed9\u65b0\u5bf9\u8c61\u7684\u5b57\u6bb5\uff0c\u4ee5\u907f\u514d\u8fdd\u53cd\u4e00\u5bf9\u4e00\u552f\u4e00\u7ea6\u675f\u3002 \u4f8b\u5982\uff0c\u5047\u8bbeentry\u5df2\u7ecf\u5982\u4e0a\u6240\u8ff0\u91cd\u590d\uff1a<\/p>\n
                                                                      \n
                                                                      detail<\/span> =<\/span> EntryDetail<\/span>.<\/span>objects<\/span>.<\/span>all<\/span>()[<\/span>0<\/span>]<\/span>\r\ndetail<\/span>.<\/span>pk<\/span> =<\/span> None<\/span>\r\ndetail<\/span>.<\/span>entry<\/span> =<\/span> entry<\/span>\r\ndetail<\/span>.<\/span>save<\/span>()<\/span>\r\n<\/pre>\n<\/div>\n
                                                                      \u4e5d\u3001\u6279\u91cf\u66f4\u65b0\u5bf9\u8c61<\/h1>\n
                                                                      \u4f7f\u7528update()<\/code>\u65b9\u6cd5\u53ef\u4ee5\u6279\u91cf\u4e3aQuerySet\u4e2d\u6240\u6709\u7684\u5bf9\u8c61\u8fdb\u884c\u66f4\u65b0\u64cd\u4f5c\u3002<\/p>\n
                                                                      \n
                                                                      # \u66f4\u65b0\u6240\u67092007\u5e74\u53d1\u5e03\u7684entry\u7684headline<\/span>\r\nEntry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>pub_date__year<\/span>=<\/span>2020<\/span>)<\/span>.<\/span>update<\/span>(<\/span>headline<\/span>=<\/span>'\u5218\u6c5f\u7684Django\u6559\u7a0b'<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                      \u53ea\u53ef\u4ee5\u5bf9\u666e\u901a\u5b57\u6bb5\u548cForeignKey\u5b57\u6bb5\u4f7f\u7528\u8fd9\u4e2a\u65b9\u6cd5\u3002\u82e5\u8981\u66f4\u65b0\u4e00\u4e2a\u666e\u901a\u5b57\u6bb5\uff0c\u53ea\u9700\u63d0\u4f9b\u4e00\u4e2a\u65b0\u7684\u5e38\u6570\u503c\u3002\u82e5\u8981\u66f4\u65b0ForeignKey\u5b57\u6bb5\uff0c\u9700\u8bbe\u7f6e\u65b0\u503c\u4e3a\u4f60\u60f3\u6307\u5411\u7684\u65b0\u6a21\u578b\u5b9e\u4f8b\u3002\u4f8b\u5982\uff1a<\/p>\n
                                                                      \n
                                                                      >>><\/span> b<\/span> =<\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>pk<\/span>=<\/span>1<\/span>)<\/span>\r\n# \u4fee\u6539\u6240\u6709\u7684Entry\uff0c\u8ba9\u4ed6\u4eec\u90fd\u5c5e\u4e8eb<\/span>\r\n>>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>all<\/span>()<\/span>.<\/span>update<\/span>(<\/span>blog<\/span>=<\/span>b<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                      update\u65b9\u6cd5\u4f1a\u88ab\u7acb\u523b\u6267\u884c\uff0c\u5e76\u8fd4\u56de\u64cd\u4f5c\u5339\u914d\u5230\u7684\u884c\u7684\u6570\u76ee\uff08\u6709\u53ef\u80fd\u4e0d\u7b49\u4e8e\u8981\u66f4\u65b0\u7684\u884c\u7684\u6570\u91cf\uff0c\u56e0\u4e3a\u6709\u4e9b\u884c\u53ef\u80fd\u5df2\u7ecf\u6709\u8fd9\u4e2a\u65b0\u503c\u4e86\uff09\u3002<\/p>\n
                                                                      \u552f\u4e00\u7684\u7ea6\u675f\u662f\uff1a\u53ea\u80fd\u8bbf\u95ee\u4e00\u5f20\u6570\u636e\u5e93\u8868\u3002\u4f60\u53ef\u4ee5\u6839\u636e\u5173\u7cfb\u5b57\u6bb5\u8fdb\u884c\u8fc7\u6ee4\uff0c\u4f46\u4f60\u53ea\u80fd\u66f4\u65b0\u6a21\u578b\u4e3b\u8868\u7684\u5b57\u6bb5\u3002\u4f8b\u5982\uff1a<\/p>\n
                                                                      \n
                                                                      >>><\/span> b<\/span> =<\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>pk<\/span>=<\/span>1<\/span>)<\/span>\r\n# Update all the headlines belonging to this Blog.<\/span>\r\n>>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>select_related<\/span>()<\/span>.<\/span>filter<\/span>(<\/span>blog<\/span>=<\/span>b<\/span>)<\/span>.<\/span>update<\/span>(<\/span>headline<\/span>=<\/span>'Everything is the same'<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                      \u8981\u6ce8\u610f\u7684\u662fupdate()\u65b9\u6cd5\u4f1a\u76f4\u63a5\u8f6c\u6362\u6210\u4e00\u4e2aSQL\u8bed\u53e5\uff0c\u5e76\u7acb\u523b\u6279\u91cf\u6267\u884c\u3002<\/p>\n
                                                                      update\u65b9\u6cd5\u4e0d\u4f1a\u8fd0\u884c\u6a21\u578b\u7684save()\u65b9\u6cd5\uff0c\u6216\u8005\u4ea7\u751fpre_save<\/code>\u6216post_save<\/code>\u4fe1\u53f7\uff08\u8c03\u7528save()<\/code>\u65b9\u6cd5\u4ea7\u751f\uff09\u6216\u8005\u670d\u4eceauto_now<\/code>\u5b57\u6bb5\u9009\u9879\u3002\u5982\u679c\u4f60\u60f3\u4fdd\u5b58QuerySet\u4e2d\u7684\u6bcf\u4e2a\u6761\u76ee\u5e76\u786e\u4fdd\u6bcf\u4e2a\u5b9e\u4f8b\u7684save()\u65b9\u6cd5\u90fd\u88ab\u8c03\u7528\uff0c\u4f60\u4e0d\u9700\u8981\u4f7f\u7528\u4efb\u4f55\u7279\u6b8a\u7684\u51fd\u6570\u6765\u5904\u7406\u3002\u53ea\u9700\u8981\u8fed\u4ee3\u5b83\u4eec\u5e76\u8c03\u7528save()\u65b9\u6cd5\uff1a<\/p>\n
                                                                      \n
                                                                      for<\/span> item<\/span> in<\/span> my_queryset<\/span>:<\/span>\r\n    item<\/span>.<\/span>save<\/span>()<\/span>\r\n<\/pre>\n<\/div>\n
                                                                      update\u65b9\u6cd5\u53ef\u4ee5\u914d\u5408F\u8868\u8fbe\u5f0f\u3002\u8fd9\u5bf9\u4e8e\u6279\u91cf\u66f4\u65b0\u540c\u4e00\u6a21\u578b\u4e2d\u67d0\u4e2a\u5b57\u6bb5\u7279\u522b\u6709\u7528\u3002\u4f8b\u5982\u589e\u52a0Blog\u4e2d\u6bcf\u4e2aEntry\u7684pingback\u4e2a\u6570\uff1a<\/p>\n
                                                                      \n
                                                                      >>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>all<\/span>()<\/span>.<\/span>update<\/span>(<\/span>number_of_pingbacks<\/span>=<\/span>F<\/span>(<\/span>'number_of_pingbacks'<\/span>)<\/span> +<\/span> 1<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                      \u7136\u800c\uff0c\u4e0efilter\u548cexclude\u5b50\u53e5\u4e2d\u7684F()\u5bf9\u8c61\u4e0d\u540c\uff0c\u5728update\u4e2d\u4f60\u4e0d\u53ef\u4ee5\u4f7f\u7528F()\u5bf9\u8c61\u8fdb\u884c\u8de8\u8868\u64cd\u4f5c\uff0c\u4f60\u53ea\u53ef\u4ee5\u5f15\u7528\u6b63\u5728\u66f4\u65b0\u7684\u6a21\u578b\u7684\u5b57\u6bb5\u3002\u5982\u679c\u4f60\u5c1d\u8bd5\u4f7f\u7528F()\u5bf9\u8c61\u5f15\u5165\u53e6\u5916\u4e00\u5f20\u8868\u7684\u5b57\u6bb5\uff0c\u5c06\u629b\u51faFieldError\u5f02\u5e38\uff1a<\/p>\n
                                                                      \n
                                                                      # \u8fd9\u5c06\u4f1a\u5bfc\u81f4\u4e00\u4e2aFieldError\u5f02\u5e38<\/span>\r\n>>><\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>update<\/span>(<\/span>headline<\/span>=<\/span>F<\/span>(<\/span>'blog__name'<\/span>))<\/span>\r\n<\/pre>\n<\/div>\n
                                                                      \u5341\u3001\u5173\u8054\u5bf9\u8c61\u7684\u67e5\u8be2<\/h1>\n
                                                                      \u5229\u7528\u672c\u8282\u4e00\u5f00\u59cb\u7684\u6a21\u578b\uff0c\u4e00\u4e2aEntry\u5bf9\u8c61e\u53ef\u4ee5\u901a\u8fc7blog\u5c5e\u6027e.blog<\/code>\u83b7\u53d6\u5173\u8054\u7684Blog\u5bf9\u8c61\u3002\u53cd\u8fc7\u6765\uff0cBlog\u5bf9\u8c61b\u53ef\u4ee5\u901a\u8fc7entry_set<\/code>\u5c5e\u6027b.entry_set.all()<\/code>\u8bbf\u95ee\u4e0e\u5b83\u5173\u8054\u7684\u6240\u6709Entry\u5bf9\u8c61\u3002<\/p>\n
                                                                      Django\u7684ORM\u7cfb\u7edf\u662f\u4e2a\u529f\u80fd\u5f3a\u5927\u3001\u4f53\u7cfb\u590d\u6742\u7684\u7cfb\u7edf\uff0c\u6211\u4eec\u5728\u5b9e\u9645\u4f7f\u7528\u4e2d\u4e0d\u4f46\u8981\u7406\u89e3\u900f\u5f7b\uff0c\u8fd8\u8981\u80fd\u6b63\u786e\u533a\u5206\u4e0d\u540c\u7684\u505a\u6cd5\uff0c\u6bd4\u5982\u8fd9\u91cc\uff1a<\/p>\n
                                                                        \n
                                                                      • Entry.objects.xxx\u662f\u83b7\u53d6Entry\u6a21\u578b\u7684\u5b9e\u4f8b\u96c6\u5408<\/li>\n
                                                                      • e.blog\u662f\u901a\u8fc7\u6b63\u5411\u5173\u8054\u5173\u7cfb\uff0c\u83b7\u53d6Blog\u6a21\u578b\u5b9e\u4f8b\u7684\u96c6\u5408<\/li>\n
                                                                      • b.entry_set.all()\u662f\u901a\u8fc7\u53cd\u5411\u5173\u8054\u5173\u7cfb\uff0c\u83b7\u53d6\u6240\u6709\u7684entry\u7ec4\u5408<\/li>\n
                                                                      • Entry.objects.filter(blog=xxx)\u662f\u5bf9\u5173\u8054\u7684blog\u5916\u952e\u5b57\u6bb5\u8fdb\u884c\u67e5\u8be2\u8fc7\u6ee4<\/li>\n<\/ul>\n
                                                                        \u5b9e\u9645\u4e0a\uff0c\u5982\u679c\u4f60\u7406\u89e3\u4e86b.entry_set<\/code>\u7b49\u540c\u4e8eEntry.objects.filter(blog=b)<\/code>\uff0c\u5c31\u80fd\u7406\u89e3\u4e0a\u9762\u7684\u5185\u5bb9\u3002<\/p>\n
                                                                        1. \u4e00\u5bf9\u591a\uff08\u5916\u952e\uff09<\/h2>\n
                                                                        \u6b63\u5411\u67e5\u8be2:<\/span><\/p>\n
                                                                        \u76f4\u63a5\u901a\u8fc7\u5706\u70b9\u52a0\u5c5e\u6027\uff0c\u8bbf\u95ee\u5916\u952e\u5bf9\u8c61\uff1a<\/p>\n
                                                                        \n
                                                                        >>><\/span> e<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>2<\/span>)<\/span>\r\n>>><\/span> e<\/span>.<\/span>blog<\/span> # \u8fd4\u56de\u5173\u8054\u7684Blog\u5bf9\u8c61<\/span>\r\n<\/pre>\n<\/div>\n
                                                                        \u8981\u6ce8\u610f\u7684\u662f\uff0c\u5bf9\u5916\u952e\u7684\u4fee\u6539\uff0c\u5fc5\u987b\u8c03\u7528save\u65b9\u6cd5\u8fdb\u884c\u4fdd\u5b58\uff0c<\/span>\u4f8b\u5982\uff1a<\/p>\n
                                                                        \n
                                                                        >>><\/span> e<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>2<\/span>)<\/span>\r\n>>><\/span> e<\/span>.<\/span>blog<\/span> =<\/span> some_blog<\/span>\r\n>>><\/span> e<\/span>.<\/span>save<\/span>()<\/span>\r\n<\/pre>\n<\/div>\n
                                                                        \u5982\u679c\u4e00\u4e2a\u5916\u952e\u5b57\u6bb5\u8bbe\u7f6e\u6709null=True<\/code>\u5c5e\u6027\uff0c\u90a3\u4e48\u53ef\u4ee5\u901a\u8fc7\u7ed9\u8be5\u5b57\u6bb5\u8d4b\u503c\u4e3aNone\u7684\u65b9\u6cd5\u79fb\u9664\u5916\u952e\u503c\uff1a<\/p>\n
                                                                        \n
                                                                        >>><\/span> e<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>2<\/span>)<\/span>\r\n>>><\/span> e<\/span>.<\/span>blog<\/span> =<\/span> None<\/span>\r\n>>><\/span> e<\/span>.<\/span>save<\/span>()<\/span> # \"UPDATE blog_entry SET blog_id = NULL ...;\"<\/span>\r\n<\/pre>\n<\/div>\n
                                                                        \u5728\u7b2c\u4e00\u6b21\u5bf9\u4e00\u4e2a\u5916\u952e\u5173\u7cfb\u8fdb\u884c\u6b63\u5411\u8bbf\u95ee\u7684\u65f6\u5019\uff0c\u5173\u7cfb\u5bf9\u8c61\u4f1a\u88ab\u7f13\u5b58\u3002\u968f\u540e\u5bf9\u540c\u6837\u5916\u952e\u5173\u7cfb\u5bf9\u8c61\u7684\u8bbf\u95ee\u4f1a\u4f7f\u7528\u8fd9\u4e2a\u7f13\u5b58\uff0c\u4f8b\u5982\uff1a<\/p>\n
                                                                        \n
                                                                        >>><\/span> e<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>2<\/span>)<\/span>\r\n>>><\/span> print<\/span>(<\/span>e<\/span>.<\/span>blog<\/span>)<\/span>  # \u8bbf\u95ee\u6570\u636e\u5e93\uff0c\u83b7\u53d6\u5b9e\u9645\u6570\u636e<\/span>\r\n>>><\/span> print<\/span>(<\/span>e<\/span>.<\/span>blog<\/span>)<\/span>  # \u4e0d\u4f1a\u8bbf\u95ee\u6570\u636e\u5e93\uff0c\u76f4\u63a5\u4f7f\u7528\u7f13\u5b58\u7684\u7248\u672c<\/span>\r\n<\/pre>\n<\/div>\n
                                                                        \u8bf7\u6ce8\u610fQuerySet\u7684select_related()<\/code>\u65b9\u6cd5\u4f1a\u9012\u5f52\u5730\u9884\u586b\u5145\u6240\u6709\u7684\u4e00\u5bf9\u591a\u5173\u7cfb\u5230\u7f13\u5b58\u4e2d\u3002\u4f8b\u5982\uff1a<\/p>\n
                                                                        \n
                                                                        >>><\/span> e<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>select_related<\/span>()<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>2<\/span>)<\/span>\r\n>>><\/span> print<\/span>(<\/span>e<\/span>.<\/span>blog<\/span>)<\/span>  # \u4e0d\u4f1a\u8bbf\u95ee\u6570\u636e\u5e93\uff0c\u76f4\u63a5\u4f7f\u7528\u7f13\u5b58<\/span>\r\n>>><\/span> print<\/span>(<\/span>e<\/span>.<\/span>blog<\/span>)<\/span>  # \u4e0d\u4f1a\u8bbf\u95ee\u6570\u636e\u5e93\uff0c\u76f4\u63a5\u4f7f\u7528\u7f13\u5b58<\/span>\r\n<\/pre>\n<\/div>\n
                                                                        \u53cd\u5411\u67e5\u8be2:<\/span><\/p>\n
                                                                        \u5982\u679c\u4e00\u4e2a\u6a21\u578b\u6709ForeignKey\uff0c\u90a3\u4e48\u8be5ForeignKey\u6240\u6307\u5411\u7684\u5916\u952e\u6a21\u578b\u7684\u5b9e\u4f8b\u53ef\u4ee5\u901a\u8fc7\u4e00\u4e2a\u7ba1\u7406\u5668\u8fdb\u884c\u53cd\u5411\u67e5\u8be2\uff0c\u8fd4\u56de\u6e90\u6a21\u578b\u7684\u6240\u6709\u5b9e\u4f8b\u3002\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u8fd9\u4e2a\u7ba1\u7406\u5668\u7684\u540d\u5b57\u4e3aFOO_set<\/code>\uff0c\u5176\u4e2dFOO\u662f\u6e90\u6a21\u578b\u7684\u5c0f\u5199\u540d\u79f0\u3002\u8be5\u7ba1\u7406\u5668\u8fd4\u56de\u7684\u67e5\u8be2\u96c6\u53ef\u4ee5\u7528\u524d\u9762\u63d0\u5230\u7684\u65b9\u5f0f\u8fdb\u884c\u8fc7\u6ee4\u548c\u64cd\u4f5c\u3002<\/p>\n
                                                                        \n
                                                                        >>><\/span> b<\/span> =<\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>1<\/span>)<\/span>\r\n>>><\/span> b<\/span>.<\/span>entry_set<\/span>.<\/span>all<\/span>()<\/span> # \u8fd4\u56de\u4e00\u4e9bEntry\u5b9e\u4f8b\uff0c\u8fd9\u4e9b\u5b9e\u4f8b\u90fd\u5173\u8054\u5230\u535a\u5ba2b<\/span>\r\n# b.entry_set \u672c\u8d28\u4e0a\u662f\u4e00\u4e2a\u7ba1\u7406\u5668<\/span>\r\n>>><\/span> b<\/span>.<\/span>entry_set<\/span>.<\/span>filter<\/span>(<\/span>headline__contains<\/span>=<\/span>'Lennon'<\/span>)<\/span>\r\n>>><\/span> b<\/span>.<\/span>entry_set<\/span>.<\/span>count<\/span>()<\/span>\r\n<\/pre>\n<\/div>\n
                                                                        \u4f60\u53ef\u4ee5\u5728ForeignKey\u5b57\u6bb5\u7684\u5b9a\u4e49\u4e2d\uff0c\u901a\u8fc7\u8bbe\u7f6erelated_name<\/code>\u6765\u91cd\u5199FOO_set<\/code>\u7684\u540d\u5b57\u3002\u4e3e\u4f8b\u8bf4\u660e\uff0c\u5982\u679c\u4f60\u4fee\u6539Entry\u6a21\u578bblog = ForeignKey(Blog, on_delete=models.CASCADE, related_name=\u2019entries\u2019)<\/code>\uff0c\u90a3\u4e48\u4e0a\u9762\u7684\u4f8b\u5b50\u4f1a\u53d8\u6210\u4e0b\u9762\u7684\u6837\u5b50\uff1a<\/p>\n
                                                                        \n
                                                                        >>><\/span> b<\/span> =<\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>1<\/span>)<\/span>\r\n>>><\/span> b<\/span>.<\/span>entries<\/span>.<\/span>all<\/span>()<\/span> \r\n\r\n>>><\/span> b<\/span>.<\/span>entries<\/span>.<\/span>filter<\/span>(<\/span>headline__contains<\/span>=<\/span>'Lennon'<\/span>)<\/span>\r\n>>><\/span> b<\/span>.<\/span>entries<\/span>.<\/span>count<\/span>()<\/span>\r\n<\/pre>\n<\/div>\n
                                                                        \u4f7f\u7528\u81ea\u5b9a\u4e49\u7684\u53cd\u5411\u7ba1\u7406\u5668:<\/span><\/p>\n
                                                                        \u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u7528\u4e8e\u53cd\u5411\u5173\u8054\u7684RelatedManager\u662f\u8be5\u6a21\u578b\u9ed8\u8ba4\u7ba1\u7406\u5668\u7684\u5b50\u7c7b\u3002\u5982\u679c\u4f60\u60f3\u4e3a\u4e00\u4e2a\u67e5\u8be2\u6307\u5b9a\u4e00\u4e2a\u4e0d\u540c\u7684\u7ba1\u7406\u5668\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528\u4e0b\u9762\u7684\u8bed\u6cd5\uff1a<\/p>\n
                                                                        \n
                                                                        from<\/span> django.db<\/span> import<\/span> models<\/span>\r\n\r\nclass<\/span> Entry<\/span>(<\/span>models<\/span>.<\/span>Model<\/span>):<\/span>\r\n    #...<\/span>\r\n    objects<\/span> =<\/span> models<\/span>.<\/span>Manager<\/span>()<\/span>  # \u9ed8\u8ba4\u7ba1\u7406\u5668<\/span>\r\n    entries<\/span> =<\/span> EntryManager<\/span>()<\/span>    # \u81ea\u5b9a\u4e49\u7ba1\u7406\u5668<\/span>\r\n\r\nb<\/span> =<\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>1<\/span>)<\/span>\r\nb<\/span>.<\/span>entry_set<\/span>(<\/span>manager<\/span>=<\/span>'entries'<\/span>)<\/span>.<\/span>all<\/span>()<\/span>\r\n<\/pre>\n<\/div>\n
                                                                        \u5f53\u7136\uff0c\u6307\u5b9a\u7684\u81ea\u5b9a\u4e49\u53cd\u5411\u7ba1\u7406\u5668\u4e5f\u53ef\u4ee5\u8c03\u7528\u5b83\u7684\u81ea\u5b9a\u4e49\u65b9\u6cd5\uff1a<\/p>\n
                                                                        \n
                                                                        b<\/span>.<\/span>entry_set<\/span>(<\/span>manager<\/span>=<\/span>'entries'<\/span>)<\/span>.<\/span>is_published<\/span>()<\/span>\r\n<\/pre>\n<\/div>\n
                                                                        2. \u591a\u5bf9\u591a<\/h2>\n
                                                                        \u591a\u5bf9\u591a\u5173\u7cfb\u7684\u4e24\u7aef\u90fd\u4f1a\u81ea\u52a8\u83b7\u5f97\u8bbf\u95ee\u53e6\u4e00\u7aef\u7684API\u3002\u8fd9\u4e9bAPI\u7684\u5de5\u4f5c\u65b9\u5f0f\u4e0e\u524d\u9762\u63d0\u5230\u7684\u201c\u53cd\u5411\u201d\u4e00\u5bf9\u591a\u5173\u7cfb\u7684\u7528\u6cd5\u4e00\u6837\u3002<\/p>\n
                                                                        \n
                                                                        e<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>3<\/span>)<\/span>\r\n\r\ne<\/span>.<\/span>authors<\/span>.<\/span>all<\/span>()<\/span> # Returns all Author objects for this Entry.<\/span>\r\ne<\/span>.<\/span>authors<\/span>.<\/span>count<\/span>()<\/span>\r\ne<\/span>.<\/span>authors<\/span>.<\/span>filter<\/span>(<\/span>name__contains<\/span>=<\/span>'John'<\/span>)<\/span>\r\n#<\/span>\r\na<\/span> =<\/span> Author<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>5<\/span>)<\/span>\r\na<\/span>.<\/span>entry_set<\/span>.<\/span>all<\/span>()<\/span> # Returns all Entry objects for this Author.<\/span>\r\n<\/pre>\n<\/div>\n
                                                                        \u4e0e\u5916\u952e\u5b57\u6bb5\u4e2d\u4e00\u6837\uff0c\u5728\u591a\u5bf9\u591a\u7684\u5b57\u6bb5\u4e2d\u4e5f\u53ef\u4ee5\u6307\u5b9arelated_name<\/code>\u540d\u3002<\/p>\n
                                                                        \uff08\u6ce8\uff1a\u5728\u4e00\u4e2a\u6a21\u578b\u4e2d\uff0c\u5982\u679c\u5b58\u5728\u591a\u4e2a\u5916\u952e\u6216\u591a\u5bf9\u591a\u7684\u5173\u7cfb\u6307\u5411\u540c\u4e00\u4e2a\u5916\u90e8\u6a21\u578b\uff0c\u5fc5\u987b\u7ed9\u4ed6\u4eec\u5206\u522b\u52a0\u4e0a\u4e0d\u540c\u7684related_name<\/code>\uff0c\u7528\u4e8e\u53cd\u5411\u67e5\u8be2\uff09<\/p>\n
                                                                        3. \u4e00\u5bf9\u4e00<\/h2>\n
                                                                        \u4e00\u5bf9\u4e00\u975e\u5e38\u7c7b\u4f3c\u591a\u5bf9\u4e00\u5173\u7cfb\uff0c\u53ef\u4ee5\u7b80\u5355\u7684\u901a\u8fc7\u6a21\u578b\u7684\u5c5e\u6027\u8bbf\u95ee\u5173\u8054\u7684\u6a21\u578b\u3002<\/p>\n
                                                                        \n
                                                                        class<\/span> EntryDetail<\/span>(<\/span>models<\/span>.<\/span>Model<\/span>):<\/span>\r\n    entry<\/span> =<\/span> models<\/span>.<\/span>OneToOneField<\/span>(<\/span>Entry<\/span>,<\/span> on_delete<\/span>=<\/span>models<\/span>.<\/span>CASCADE<\/span>)<\/span>\r\n    details<\/span> =<\/span> models<\/span>.<\/span>TextField<\/span>()<\/span>\r\n\r\ned<\/span> =<\/span> EntryDetail<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>2<\/span>)<\/span>\r\ned<\/span>.<\/span>entry<\/span> # Returns the related Entry object.<\/span>\r\n<\/pre>\n<\/div>\n
                                                                        \u4e0d\u540c\u4e4b\u5904\u5728\u4e8e\u53cd\u5411\u67e5\u8be2\u7684\u65f6\u5019\u3002\u4e00\u5bf9\u4e00\u5173\u7cfb\u4e2d\u7684\u5173\u8054\u6a21\u578b\u540c\u6837\u5177\u6709\u4e00\u4e2a\u7ba1\u7406\u5668\u5bf9\u8c61\uff0c\u4f46\u662f\u8be5\u7ba1\u7406\u5668\u8868\u793a\u4e00\u4e2a\u5355\u4e00\u7684\u5bf9\u8c61\u800c\u4e0d\u662f\u5bf9\u8c61\u7684\u96c6\u5408\uff1a<\/p>\n
                                                                        \n
                                                                        e<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>2<\/span>)<\/span>\r\ne<\/span>.<\/span>entrydetail<\/span> # \u8fd4\u56de\u5173\u8054\u7684EntryDetail\u5bf9\u8c61<\/span>\r\n<\/pre>\n<\/div>\n
                                                                        \u5982\u679c\u6ca1\u6709\u5bf9\u8c61\u8d4b\u503c\u7ed9\u8fd9\u4e2a\u5173\u7cfb\uff0cDjango\u5c06\u629b\u51fa\u4e00\u4e2aDoesNotExist\u5f02\u5e38\u3002 \u53ef\u4ee5\u7ed9\u53cd\u5411\u5173\u8054\u8fdb\u884c\u8d4b\u503c\uff0c\u65b9\u6cd5\u548c\u6b63\u5411\u7684\u5173\u8054\u4e00\u6837\uff1a<\/p>\n
                                                                        \n
                                                                        e.entrydetail = ed\r\n<\/pre>\n<\/div>\n
                                                                        4. \u53cd\u5411\u5173\u8054\u662f\u5982\u4f55\u5b9e\u73b0\u7684\uff1f<\/h2>\n
                                                                        \u4e00\u4e9bORM\u6846\u67b6\u9700\u8981\u4f60\u5728\u5173\u7cfb\u7684\u4e24\u7aef\u90fd\u8fdb\u884c\u5b9a\u4e49\u3002Django\u7684\u5f00\u53d1\u8005\u8ba4\u4e3a\u8fd9\u8fdd\u53cd\u4e86DRY (Don\u2019t Repeat Yourself)\u539f\u5219\uff0c\u6240\u4ee5\u5728Django\u4e2d\u4f60\u53ea\u9700\u8981\u5728\u4e00\u7aef\u8fdb\u884c\u5b9a\u4e49\u3002<\/p>\n
                                                                        \u90a3\u4e48\u8fd9\u662f\u600e\u4e48\u5b9e\u73b0\u7684\u5462\uff1f\u56e0\u4e3a\u5728\u5173\u8054\u7684\u6a21\u578b\u7c7b\u6ca1\u6709\u88ab\u52a0\u8f7d\u4e4b\u524d\uff0c\u4e00\u4e2a\u6a21\u578b\u7c7b\u6839\u672c\u4e0d\u77e5\u9053\u6709\u54ea\u4e9b\u7c7b\u548c\u5b83\u5173\u8054\u3002<\/p>\n
                                                                        \u7b54\u6848\u5728app registry<\/code>\uff01\u5728Django\u542f\u52a8\u7684\u65f6\u5019\uff0c\u5b83\u4f1a\u5bfc\u5165\u6240\u6709INSTALLED_APPS<\/code>\u4e2d\u7684\u5e94\u7528\u548c\u6bcf\u4e2a\u5e94\u7528\u4e2d\u7684\u6a21\u578b\u6a21\u5757\u3002\u6bcf\u521b\u5efa\u4e00\u4e2a\u65b0\u7684\u6a21\u578b\u65f6\uff0cDjango\u4f1a\u81ea\u52a8\u6dfb\u52a0\u53cd\u5411\u7684\u5173\u7cfb\u5230\u6240\u6709\u5173\u8054\u7684\u6a21\u578b\u3002\u5982\u679c\u5173\u8054\u7684\u6a21\u578b\u8fd8\u6ca1\u6709\u5bfc\u5165\uff0cDjango\u5c06\u4fdd\u5b58\u5173\u8054\u7684\u8bb0\u5f55\u5e76\u5728\u5173\u8054\u7684\u6a21\u578b\u5bfc\u5165\u65f6\u6dfb\u52a0\u8fd9\u4e9b\u5173\u7cfb\u3002<\/p>\n
                                                                        \u7531\u4e8e\u8fd9\u4e2a\u539f\u56e0\uff0c\u5c06\u6a21\u578b\u6240\u5728\u7684\u5e94\u7528\u90fd\u5b9a\u4e49\u5728INSTALLED_APPS<\/code>\u7684\u5e94\u7528\u5217\u8868\u4e2d\u5c31\u663e\u5f97\u7279\u522b\u91cd\u8981\u3002\u5426\u5219\uff0c\u53cd\u5411\u5173\u8054\u5c06\u4e0d\u80fd\u6b63\u786e\u5de5\u4f5c\u3002<\/p>\n
                                                                        5. \u901a\u8fc7\u5173\u8054\u5bf9\u8c61\u8fdb\u884c\u67e5\u8be2<\/h2>\n
                                                                        \u6d89\u53ca\u5173\u8054\u5bf9\u8c61\u7684\u67e5\u8be2\u4e0e\u6b63\u5e38\u503c\u7684\u5b57\u6bb5\u67e5\u8be2\u9075\u5faa\u540c\u6837\u7684\u89c4\u5219\u3002\u5f53\u4f60\u6307\u5b9a\u67e5\u8be2\u9700\u8981\u5339\u914d\u7684\u503c\u65f6\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528\u4e00\u4e2a\u5bf9\u8c61\u5b9e\u4f8b\u6216\u8005\u5bf9\u8c61\u7684\u4e3b\u952e\u503c\u3002<\/p>\n
                                                                        \u4f8b\u5982\uff0c\u5982\u679c\u4f60\u6709\u4e00\u4e2aid=5\u7684Blog\u5bf9\u8c61b\uff0c\u4e0b\u9762\u7684\u4e09\u4e2a\u67e5\u8be2\u5c06\u662f\u5b8c\u5168\u4e00\u6837\u7684\uff1a<\/p>\n
                                                                        \n
                                                                        Entry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>blog<\/span>=<\/span>b<\/span>)<\/span> # \u4f7f\u7528\u5bf9\u8c61\u5b9e\u4f8b<\/span>\r\nEntry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>blog<\/span>=<\/span>b<\/span>.<\/span>id<\/span>)<\/span> # \u4f7f\u7528\u5b9e\u4f8b\u7684id<\/span>\r\nEntry<\/span>.<\/span>objects<\/span>.<\/span>filter<\/span>(<\/span>blog<\/span>=<\/span>5<\/span>)<\/span> # \u76f4\u63a5\u4f7f\u7528id<\/span>\r\n<\/pre>\n<\/div>\n
                                                                        \u5341\u4e00\u3001\u5173\u8054\u5bf9\u8c61\u7684\u589e\u5220\u6539<\/h1>\n
                                                                        \u9664\u4e86\u5728\u524d\u9762\u5b9a\u4e49\u7684QuerySet\u65b9\u6cd5\u4e4b\u5916\uff0c\u7ba1\u7406\u5668\u8fd8\u6709\u5176\u5b83\u65b9\u6cd5\u7528\u4e8e\u5904\u7406\u5173\u8054\u7684\u5bf9\u8c61\u96c6\u5408\u3002\u4e0b\u9762\u662f\u6bcf\u4e2a\u65b9\u6cd5\u7684\u6982\u62ec\u3002<\/p>\n
                                                                          \n
                                                                        • add(obj1, obj2, …)\uff1a\u6dfb\u52a0\u6307\u5b9a\u7684\u6a21\u578b\u5bf9\u8c61\u5230\u5173\u8054\u7684\u5bf9\u8c61\u96c6\u4e2d\u3002<\/li>\n
                                                                        • create(**kwargs)\uff1a\u521b\u5efa\u4e00\u4e2a\u65b0\u7684\u5bf9\u8c61\uff0c\u5c06\u5b83\u4fdd\u5b58\u5e76\u653e\u5728\u5173\u8054\u7684\u5bf9\u8c61\u96c6\u4e2d\u3002\u8fd4\u56de\u65b0\u521b\u5efa\u7684\u5bf9\u8c61\u3002<\/li>\n
                                                                        • remove(obj1, obj2, …)\uff1a\u4ece\u5173\u8054\u7684\u5bf9\u8c61\u96c6\u4e2d\u5220\u9664\u6307\u5b9a\u7684\u6a21\u578b\u5bf9\u8c61\u3002<\/li>\n
                                                                        • clear()\uff1a\u6e05\u7a7a\u5173\u8054\u7684\u5bf9\u8c61\u96c6\u3002<\/li>\n
                                                                        • set([obj1,obj2…])\uff1a\u91cd\u7f6e\u5173\u8054\u7684\u5bf9\u8c61\u96c6\u3002<\/li>\n<\/ul>\n
                                                                          \u82e5\u8981\u4e00\u6b21\u6027\u7ed9\u5173\u8054\u7684\u5bf9\u8c61\u96c6\u8d4b\u503c\uff0c\u4f7f\u7528set()\u65b9\u6cd5\uff0c\u5e76\u7ed9\u5b83\u8d4b\u503c\u4e00\u4e2a\u53ef\u8fed\u4ee3\u7684\u5bf9\u8c61\u96c6\u5408\u6216\u8005\u4e00\u4e2a\u4e3b\u952e\u503c\u7684\u5217\u8868\u3002\u4f8b\u5982\uff1a<\/p>\n
                                                                          \n
                                                                          b<\/span> =<\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>1<\/span>)<\/span>\r\nb<\/span>.<\/span>entry_set<\/span>.<\/span>set<\/span>([<\/span>e1<\/span>,<\/span> e2<\/span>])<\/span>\r\n<\/pre>\n<\/div>\n
                                                                          \u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0ce1\u548ce2\u53ef\u4ee5\u662f\u5b8c\u6574\u7684Entry\u5b9e\u4f8b\uff0c\u4e5f\u53ef\u4ee5\u662f\u6574\u6570\u7684\u4e3b\u952e\u503c\u3002<\/p>\n
                                                                          \u5982\u679cclear()\u65b9\u6cd5\u53ef\u7528\uff0c\u90a3\u4e48\u5728\u5c06\u53ef\u8fed\u4ee3\u5bf9\u8c61\u4e2d\u7684\u6210\u5458\u6dfb\u52a0\u5230\u96c6\u5408\u4e2d\u4e4b\u524d\uff0c\u5c06\u4eceentry_set<\/code>\u4e2d\u5220\u9664\u6240\u6709\u5df2\u7ecf\u5b58\u5728\u7684\u5bf9\u8c61\u3002\u5982\u679cclear()\u65b9\u6cd5\u4e0d\u53ef\u7528\uff0c\u90a3\u4e48\u5c06\u76f4\u63a5\u6dfb\u52a0\u53ef\u8fed\u4ee3\u5bf9\u8c61\u4e2d\u7684\u6210\u5458\u800c\u4e0d\u4f1a\u5220\u9664\u6240\u6709\u5df2\u5b58\u5728\u7684\u5bf9\u8c61\u3002<\/p>\n
                                                                          \u8fd9\u8282\u4e2d\u7684\u6bcf\u4e2a\u53cd\u5411\u64cd\u4f5c\u90fd\u5c06\u7acb\u5373\u5728\u6570\u636e\u5e93\u5185\u6267\u884c\u3002\u6240\u6709\u7684\u589e\u52a0\u3001\u521b\u5efa\u548c\u5220\u9664\u64cd\u4f5c\u4e5f\u5c06\u7acb\u523b\u81ea\u52a8\u5730\u4fdd\u5b58\u5230\u6570\u636e\u5e93\u5185\u3002<\/p>\n
                                                                          \u4e0b\u9762\u662f\u66f4\u591a\u7684\u4f7f\u7528\u6848\u4f8b\uff1a<\/p>\n
                                                                          \n
                                                                          # \u589e\u52a0<\/span>\r\n>>><\/span> b<\/span> =<\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>1<\/span>)<\/span>\r\n>>><\/span> e<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>2<\/span>)<\/span>\r\n>>><\/span> b<\/span>.<\/span>entry_set<\/span>.<\/span>add<\/span>(<\/span>e<\/span>)<\/span> # Associates Entry e with Blog b.<\/span>\r\n\r\n# \u521b\u5efa<\/span>\r\n# \u6b64\u65f6\u4e0d\u9700\u8981\u8c03\u7528e.save()\uff0c\u4f1a\u81ea\u52a8\u4fdd\u5b58<\/span>\r\n>>><\/span> e<\/span> =<\/span> b<\/span>.<\/span>entry_set<\/span>.<\/span>create<\/span>(<\/span>\r\n...<\/span>     headline<\/span>=<\/span>'Hello'<\/span>,<\/span>\r\n...<\/span>     body_text<\/span>=<\/span>'Hi'<\/span>,<\/span>\r\n...<\/span>     pub_date<\/span>=<\/span>datetime<\/span>.<\/span>date<\/span>(<\/span>2005<\/span>,<\/span> 1<\/span>,<\/span> 1<\/span>)<\/span>\r\n...<\/span> )<\/span>\r\n\r\n# \u548c\u4e0a\u9762\u76f8\u5f53<\/span>\r\n>>><\/span> b<\/span> =<\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>1<\/span>)<\/span>\r\n>>><\/span> e<\/span> =<\/span> Entry<\/span>(<\/span>\r\n...<\/span>     blog<\/span>=<\/span>b<\/span>,<\/span>\r\n...<\/span>     headline<\/span>=<\/span>'Hello'<\/span>,<\/span>\r\n...<\/span>     body_text<\/span>=<\/span>'Hi'<\/span>,<\/span>\r\n...<\/span>     pub_date<\/span>=<\/span>datetime<\/span>.<\/span>date<\/span>(<\/span>2005<\/span>,<\/span> 1<\/span>,<\/span> 1<\/span>)<\/span>\r\n...<\/span> )<\/span>\r\n>>><\/span> e<\/span>.<\/span>save<\/span>(<\/span>force_insert<\/span>=<\/span>True<\/span>)<\/span>\r\n\r\n# \u5220\u9664<\/span>\r\n>>><\/span> b<\/span> =<\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>1<\/span>)<\/span>\r\n>>><\/span> e<\/span> =<\/span> Entry<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>2<\/span>)<\/span>\r\n>>><\/span> b<\/span>.<\/span>entry_set<\/span>.<\/span>remove<\/span>(<\/span>e<\/span>)<\/span> # Disassociates Entry e from Blog b.<\/span>\r\n\r\n# \u6e05\u7a7a<\/span>\r\n>>><\/span> b<\/span> =<\/span> Blog<\/span>.<\/span>objects<\/span>.<\/span>get<\/span>(<\/span>id<\/span>=<\/span>1<\/span>)<\/span>\r\n>>><\/span> b<\/span>.<\/span>entry_set<\/span>.<\/span>clear<\/span>()<\/span>\r\n\r\n# \u6279\u91cf\u8bbe\u7f6e<\/span>\r\n>>><\/span> new_list<\/span> =<\/span> [<\/span>obj1<\/span>,<\/span> obj2<\/span>,<\/span> obj3<\/span>]<\/span>\r\n>>><\/span> e<\/span>.<\/span>related_set<\/span>.<\/span>set<\/span>(<\/span>new_list<\/span>)<\/span>\r\n<\/pre>\n<\/div>\n
                                                                          \u5341\u4e8c\u3001\u4f7f\u7528\u539f\u751fSQL\u8bed\u53e5<\/h1>\n
                                                                          \u5982\u679c\u4f60\u53d1\u73b0\u9700\u8981\u7f16\u5199\u7684Django\u67e5\u8be2\u8bed\u53e5\u592a\u590d\u6742\uff0c\u4f60\u53ef\u4ee5\u56de\u5f52\u5230\u624b\u5de5\u7f16\u5199SQL\u8bed\u53e5\u3002Django\u5bf9\u4e8e\u7f16\u5199\u539f\u751f\u7684SQL\u67e5\u8be2\u6709\u8bb8\u591a\u9009\u9879\u3002<\/p>\n
                                                                          \u6700\u540e\uff0c\u9700\u8981\u6ce8\u610f\u7684\u662fDjango\u7684\u6570\u636e\u5e93\u5c42\u53ea\u662f\u4e00\u4e2a\u6570\u636e\u5e93\u63a5\u53e3\u3002\u4f60\u53ef\u4ee5\u5229\u7528\u5176\u5b83\u7684\u5de5\u5177\u3001\u7f16\u7a0b\u8bed\u8a00\u6216\u6570\u636e\u5e93\u6846\u67b6\u6765\u8bbf\u95ee\u6570\u636e\u5e93\uff0cDjango\u6ca1\u6709\u5f3a\u5236\u6307\u5b9a\u4f60\u975e\u8981\u4f7f\u7528\u5b83\u7684\u67d0\u4e2a\u529f\u80fd\u6216\u6a21\u5757\u3002<\/p>\n
                                                                           <\/p>\n","protected":false},"excerpt":{"rendered":"
                                                                          \u67e5\u8be2\u64cd\u4f5c https:\/\/www.liujiangblog.com\/course\/django\/129 \u67e5\u8be2\u64cd\u4f5c\u662fDjango\u7684ORM\u6846\u67b6\u4e2d\u6700\u91cd\u8981\u7684\u5185\u5bb9\u4e4b\u4e00\u3002\u6211\u4eec\u5efa\u7acb\u6a21\u578b\u3001\u4fdd\u5b58\u6570\u636e\u4e3a\u7684\u5c31\u662f\u5728\u9700\u8981\u7684\u65f6\u5019\u53ef\u4ee5\u67e5\u8be2\u5f97\u5230\u6570\u636e\u3002Django\u81ea\u52a8\u4e3a\u6240\u6709 …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11],"tags":[],"class_list":["post-121","post","type-post","status-publish","format-standard","hentry","category-django"],"_links":{"self":[{"href":"http:\/\/www.jichangqing.net\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/121","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.jichangqing.net\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.jichangqing.net\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.jichangqing.net\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.jichangqing.net\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=121"}],"version-history":[{"count":1,"href":"http:\/\/www.jichangqing.net\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/121\/revisions"}],"predecessor-version":[{"id":122,"href":"http:\/\/www.jichangqing.net\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/121\/revisions\/122"}],"wp:attachment":[{"href":"http:\/\/www.jichangqing.net\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=121"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.jichangqing.net\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=121"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.jichangqing.net\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=121"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}