{"id":5794,"date":"2022-04-03T10:03:53","date_gmt":"2022-04-03T02:03:53","guid":{"rendered":"https:\/\/egonlin.com\/?p=5794"},"modified":"2022-04-10T16:52:00","modified_gmt":"2022-04-10T08:52:00","slug":"05-01-django%e4%b9%8b%e6%a8%a1%e5%9e%8b%e5%b1%82%e7%ac%ac%e4%b8%80%e7%af%87%ef%bc%9a%e5%8d%95%e8%a1%a8%e6%93%8d%e4%bd%9c","status":"publish","type":"post","link":"https:\/\/egonlin.com\/?p=5794","title":{"rendered":"05-01 \u6a21\u578b\u5c42\u7b2c\u4e00\u7bc7\uff1a\u5355\u8868\u64cd\u4f5c"},"content":{"rendered":"

Django\u4e4b\u6a21\u578b\u5c42\u7b2c\u4e00\u7bc7\uff1a\u5355\u8868\u64cd\u4f5c<\/h1>\n

\u4e00 ORM\u7b80\u4ecb<\/h1>\n

\"\"<\/div><\/p>\n

\u200b \u6211\u4eec\u5728\u4f7f\u7528Django\u6846\u67b6\u5f00\u53d1web\u5e94\u7528\u7684\u8fc7\u7a0b\u4e2d\uff0c\u4e0d\u53ef\u907f\u514d\u5730\u4f1a\u6d89\u53ca\u5230\u6570\u636e\u7684\u7ba1\u7406\u64cd\u4f5c\uff08\u5982\u589e\u3001\u5220\u3001\u6539\u3001\u67e5\uff09\uff0c\u800c\u4e00\u65e6\u8c08\u5230\u6570\u636e\u7684\u7ba1\u7406\u64cd\u4f5c\uff0c\u5c31\u9700\u8981\u7528\u5230\u6570\u636e\u5e93\u7ba1\u7406\u8f6f\u4ef6\uff0c\u4f8b\u5982mysql\u3001oracle\u3001Microsoft SQL Server\u7b49\u3002<\/p>\n

\u200b \u5982\u679c\u5e94\u7528\u7a0b\u5e8f\u9700\u8981\u64cd\u4f5c\u6570\u636e\uff08\u6bd4\u5982\u5c06\u7528\u6237\u6ce8\u518c\u4fe1\u606f\u6c38\u4e45\u5b58\u653e\u8d77\u6765\uff09\uff0c\u90a3\u4e48\u6211\u4eec\u9700\u8981\u5728\u5e94\u7528\u7a0b\u5e8f\u4e2d\u7f16\u5199\u539f\u751fsql\u8bed\u53e5\uff0c\u7136\u540e\u4f7f\u7528pymysql\u6a21\u5757\u8fdc\u7a0b\u64cd\u4f5cmysql\u6570\u636e\u5e93\uff0c\u8be6\u89c1\u56fe1<\/p>\n

\u4f46\u662f\u76f4\u63a5\u7f16\u5199\u539f\u751fsql\u8bed\u53e5\u4f1a\u5b58\u5728\u4e24\u65b9\u9762\u7684\u95ee\u9898\uff0c\u4e25\u91cd\u5f71\u54cd\u5f00\u53d1\u6548\u7387\uff0c\u5982\u4e0b<\/p>\n

#1. sql\u8bed\u53e5\u7684\u6267\u884c\u6548\u7387\uff1a\u5e94\u7528\u5f00\u53d1\u7a0b\u5e8f\u5458\u9700\u8981\u8017\u8d39\u4e00\u5927\u90e8\u5206\u7cbe\u529b\u53bb\u4f18\u5316sql\u8bed\u53e5\n#2. \u6570\u636e\u5e93\u8fc1\u79fb\uff1a\u9488\u5bf9mysql\u5f00\u53d1\u7684sql\u8bed\u53e5\u65e0\u6cd5\u76f4\u63a5\u5e94\u7528\u5230oracle\u6570\u636e\u5e93\u4e0a\uff0c\u4e00\u65e6\u9700\u8981\u8fc1\u79fb\u6570\u636e\u5e93\uff0c\u4fbf\u9700\u8981\u8003\u8651\u8de8\u5e73\u53f0\u95ee\u9898<\/code><\/pre>\n
\u4e3a\u4e86\u89e3\u51b3\u4e0a\u8ff0\u95ee\u9898\uff0cdjango\u5f15\u5165\u4e86ORM\u7684\u6982\u5ff5\uff0cORM\u5168\u79f0Object Relational Mapping\uff0c\u5373\u5bf9\u8c61\u5173\u7cfb\u6620\u5c04\uff0c\u662f\u5728pymysq\u4e4b\u4e0a\u53c8\u8fdb\u884c\u4e86\u4e00\u5c42\u5c01\u88c5\uff0c\u5bf9\u4e8e\u6570\u636e\u7684\u64cd\u4f5c\uff0c\u6211\u4eec\u65e0\u9700\u518d\u53bb\u7f16\u5199\u539f\u751fsql\uff0c\u53d6\u4ee3\u4ee3\u4e4b\u7684\u662f\u57fa\u4e8e\u9762\u5411\u5bf9\u8c61\u7684\u601d\u60f3\u53bb\u7f16\u5199\u7c7b\u3001\u5bf9\u8c61\u3001\u8c03\u7528\u76f8\u5e94\u7684\u65b9\u6cd5\u7b49\uff0cORM\u4f1a\u5c06\u5176\u8f6c\u6362\/\u6620\u5c04\u6210\u539f\u751fSQL\u7136\u540e\u4ea4\u7ed9pymysql\u6267\u884c\uff0c\u8be6\u89c1\u56fe2<\/p>\n
\u3002\u3002\u3002\u3002\u3002\u3002\u63d2\u56fe1<\/p>\n
\"\"<\/div><\/p>\n
\u539f\u751fSQL\u4e0eORM\u7684\u5bf9\u5e94\u5173\u7cfb\u793a\u4f8b\u5982\u4e0b<\/p>\n
\u63d2\u56fe2<\/p>\n
\u82e5\u56fe\u7247\u9700\u8981\u4fee\u6539\uff0c\u5219\u67e5\u770b\u5730\u5740\uff1ahttps:\/\/www.processon.com\/diagraming\/588d8be2e4b098bf4d1ecb1d<\/a><\/p>\n
\"\"<\/div><\/p>\n
\u5982\u6b64\uff0c\u5f00\u53d1\u4eba\u5458\u65e2\u4e0d\u7528\u518d\u53bb\u8003\u8651\u539f\u751fSQL\u7684\u4f18\u5316\u95ee\u9898\uff0c\u4e5f\u4e0d\u7528\u8003\u8651\u6570\u636e\u5e93\u8fc1\u79fb\u7684\u95ee\u9898\uff0cORM\u90fd\u5e2e\u6211\u4eec\u505a\u4e86\u4f18\u5316\u4e14\u652f\u6301\u591a\u79cd\u6570\u636e\u5e93\uff0c\u8fd9\u6781\u5927\u5730\u63d0\u5347\u4e86\u6211\u4eec\u7684\u5f00\u53d1\u6548\u7387\uff0c\u4e0b\u9762\u5c31\u8ba9\u6211\u4eec\u6765\u8be6\u7ec6\u5b66\u4e60ORM\u7684\u4f7f\u7528\u5427<\/p>\n
\"\"<\/div><\/p>\n
\u4e8c \u5355\u8868\u64cd\u4f5c<\/h1>\n
2.1 \u6309\u6b65\u9aa4\u521b\u5efa\u8868<\/h2>\n
2.1.1 \u521b\u5efadjango\u9879\u76ee\uff0c\u65b0\u5efa\u540d\u4e3aapp01\u7684app\uff0c\u5728app01\u7684models.py\u4e2d\u521b\u5efa\u6a21\u578b<\/h5>\n
class Employee(models.Model): # \u5fc5\u987b\u662fmodels.Model\u7684\u5b50\u7c7b\n    id=models.AutoField(primary_key=True)\n\n    name=models.CharField(max_length=16)\n\n    gender=models.BooleanField(default=1)\n\n    birth=models.DateField()\n\n    department=models.CharField(max_length=30)\n\n    salary=models.DecimalField(max_digits=10,decimal_places=1)<\/code><\/pre>\n
2.1.2 django\u7684orm\u652f\u6301\u591a\u79cd\u6570\u636e\u5e93\uff0c\u5982\u679c\u60f3\u5c06\u4e0a\u8ff0\u6a21\u578b\u8f6c\u4e3amysql\u6570\u636e\u5e93\u4e2d\u7684\u8868\uff0c\u9700\u8981settings.py\u4e2d<\/h5>\n
# \u5220\u9664\\\u6ce8\u91ca\u6389\u539f\u6765\u7684DATABASES\u914d\u7f6e\u9879\uff0c\u65b0\u589e\u4e0b\u8ff0\u914d\u7f6e\nDATABASES = {\n    'default': {\n        'ENGINE': 'django.db.backends.mysql', # \u4f7f\u7528mysql\u6570\u636e\u5e93\n        'NAME': 'db1',          # \u8981\u8fde\u63a5\u7684\u6570\u636e\u5e93\n        'USER': 'root',         # \u94fe\u63a5\u6570\u636e\u5e93\u7684\u7528\u4e8e\u540d\n        'PASSWORD': '',         # \u94fe\u63a5\u6570\u636e\u5e93\u7684\u7528\u4e8e\u540d                  \n        'HOST': '127.0.0.1',    # mysql\u670d\u52a1\u76d1\u542c\u7684ip  \n        'PORT': 3306,           # mysql\u670d\u52a1\u76d1\u542c\u7684\u7aef\u53e3  \n        'ATOMIC_REQUEST': True, #\u8bbe\u7f6e\u4e3aTrue\u4ee3\u8868\u540c\u4e00\u4e2ahttp\u8bf7\u6c42\u6240\u5bf9\u5e94\u7684\u6240\u6709sql\u90fd\u653e\u5728\u4e00\u4e2a\u4e8b\u52a1\u4e2d\u6267\u884c \n                                #(\u8981\u4e48\u6240\u6709\u90fd\u6210\u529f\uff0c\u8981\u4e48\u6240\u6709\u90fd\u5931\u8d25)\uff0c\u8fd9\u662f\u5168\u5c40\u6027\u7684\u914d\u7f6e\uff0c\u5982\u679c\u8981\u5bf9\u67d0\u4e2a\n                                #http\u8bf7\u6c42\u653e\u6c34\uff08\u7136\u540e\u81ea\u5b9a\u4e49\u4e8b\u52a1\uff09\uff0c\u53ef\u4ee5\u7528non_atomic_requests\u4fee\u9970\u5668 \n        'OPTIONS': {\n            "init_command": "SET storage_engine=INNODB", #\u8bbe\u7f6e\u521b\u5efa\u8868\u7684\u5b58\u50a8\u5f15\u64ce\u4e3aINNODB\n        }\n    }\n}<\/code><\/pre>\n
2.1.3 \u5728\u94fe\u63a5mysql\u6570\u636e\u5e93\u524d\uff0c\u5fc5\u987b\u4e8b\u5148\u521b\u5efa\u597d\u6570\u636e\u5e93<\/h5>\n
mysql> create database db1; # \u6570\u636e\u5e93\u540d\u5fc5\u987b\u4e0esettings.py\u4e2d\u6307\u5b9a\u7684\u540d\u5b57\u5bf9\u5e94\u4e0a<\/code><\/pre>\n
2.1.4  \u5176\u5b9epython\u89e3\u91ca\u5668\u5728\u8fd0\u884cdjango\u7a0b\u5e8f\u65f6\uff0cdjango\u7684orm\u5e95\u5c42\u64cd\u4f5c\u6570\u636e\u5e93\u7684python\u6a21\u5757\u9ed8\u8ba4\u662fmysqldb\u800c\u975epymysql\uff0c\u7136\u800c\u5bf9\u4e8e\u89e3\u91ca\u5668\u800c\u8a00\uff0cpython2.x\u89e3\u91ca\u5668\u652f\u6301\u7684\u64cd\u4f5c\u6570\u636e\u5e93\u7684\u6a21\u5757\u662fmysqldb\uff0c\u800cpython3.x\u89e3\u91ca\u5668\u652f\u6301\u7684\u64cd\u4f5c\u6570\u636e\u5e93\u7684\u6a21\u5757\u5219\u662fpymysql\uff0c\uff0c\u6beb\u65e0\u7591\u95ee\uff0c\u76ee\u524d\u6211\u4eec\u7684django\u7a0b\u5e8f\u90fd\u662f\u8fd0\u884c\u4e8epython3.x\u89e3\u91ca\u5668\u4e0b\uff0c\u4e8e\u662f\u6211\u4eec\u9700\u8981\u4fee\u6539django\u7684orm\u9ed8\u8ba4\u64cd\u4f5c\u6570\u636e\u5e93\u7684\u6a21\u5757\u4e3apymysql\uff0c\u5177\u4f53\u505a\u6cd5\u5982\u4e0b<\/h5>\n
\"\"<\/div><\/p>\n
2.1.5 \u786e\u4fdd\u914d\u7f6e\u6587\u4ef6settings.py\u4e2d\u7684INSTALLED_APPS\u4e2d\u6dfb\u52a0\u6211\u4eec\u521b\u5efa\u7684app\u540d\u79f0,django2.x\u4e0edjango1.x\u5904\u7406\u6dfb\u52a0\u65b9\u5f0f\u4e0d\u540c<\/h5>\n
# django1.x\u7248\u672c\uff0c\u5728\u4e0b\u8ff0\u5217\u8868\u4e2d\u65b0\u589e\u6211\u4eec\u7684app\u540d\u5b57\u5373\u53ef\nINSTALLED_APPS = [\n    'django.contrib.admin',\n    'django.contrib.auth',\n    'django.contrib.contenttypes',\n    'django.contrib.sessions',\n    'django.contrib.messages',\n    'django.contrib.staticfiles',\n    'app01',\n    # 'app02' # \u82e5\u6709\u65b0\u589e\u7684app\uff0c\u4f9d\u6b21\u6dfb\u52a0\u5373\u53ef\n]\n\n# django2.x\u7248\u672c\uff0c\u53ef\u80fd\u4f1a\u5e2e\u6211\u4eec\u81ea\u52a8\u6dfb\u52a0app\uff0c\u53ea\u662f\u6362\u4e86\u4e00\u79cd\u6dfb\u52a0\u65b9\u5f0f\nINSTALLED_APPS = [\n    'django.contrib.admin',\n    'django.contrib.auth',\n    'django.contrib.contenttypes',\n    'django.contrib.sessions',\n    'django.contrib.messages',\n    'django.contrib.staticfiles',\n    'app01.apps.App01Config', # \u5982\u679c\u9ed8\u8ba4\u5df2\u7ecf\u6dfb\u52a0\u4e86\uff0c\u5219\u65e0\u9700\u91cd\u590d\u6dfb\u52a0\n    # 'app02.apps.App02Config', # \u82e5\u6709\u65b0\u589e\u7684app\uff0c\u6309\u7167\u89c4\u5f8b\u4f9d\u6b21\u6dfb\u52a0\u5373\u53ef\n]\n<\/code><\/pre>\n
2.1.6 \u5982\u679c\u60f3\u6253\u5370orm\u8f6c\u6362\u8fc7\u7a0b\u4e2d\u7684sql\uff0c\u9700\u8981\u5728settings\u4e2d\u8fdb\u884c\u914d\u7f6e\u65e5\u5fd7\uff1a<\/h5>\n
LOGGING = {\n    'version': 1,\n    'disable_existing_loggers': False,\n    'handlers': {\n        'console':{\n            'level':'DEBUG',\n            'class':'logging.StreamHandler',\n        },\n    },\n    'loggers': {\n        'django.db.backends': {\n            'handlers': ['console'],\n            'propagate': True,\n            'level':'DEBUG',\n        },\n    }\n}<\/code><\/pre>\n
2.1.7 \u6700\u540e\u5728\u547d\u4ee4\u884c\u4e2d\u6267\u884c\u4e24\u6761\u6570\u636e\u5e93\u8fc1\u79fb\u547d\u4ee4\uff0c\u5373\u53ef\u5728\u6307\u5b9a\u7684\u6570\u636e\u5e93db1\u4e2d\u521b\u5efa\u8868 \uff1a<\/h5>\n
$ python manage.py makemigrations\n$ python manage.py migrate\n\n# \u6ce8\u610f\uff1a\n# 1\u3001makemigrations\u53ea\u662f\u751f\u6210\u4e00\u4e2a\u6570\u636e\u5e93\u8fc1\u79fb\u8bb0\u5f55\u7684\u6587\u4ef6\uff0c\u800cmigrate\u624d\u662f\u5c06\u66f4\u6539\u771f\u6b63\u63d0\u4ea4\u5230\u6570\u636e\u5e93\u6267\u884c\n# 2\u3001\u6570\u636e\u5e93\u8fc1\u79fb\u8bb0\u5f55\u7684\u6587\u4ef6\u5b58\u653e\u4e8eapp01\u4e0b\u7684migrations\u6587\u4ef6\u5939\u91cc\n# 3\u3001\u4e86\u89e3\uff1a\u4f7f\u7528\u547d\u4ee4python manage.py showmigrations\u53ef\u4ee5\u67e5\u770b\u6ca1\u6709\u6267\u884cmigrate\u7684\u6587\u4ef6<\/code><\/pre>\n
\u6ce8\u610f1\uff1a\u5728\u4f7f\u7528\u7684\u662fdjango1.x\u7248\u672c\u65f6\uff0c\u5982\u679c\u62a5\u5982\u4e0b\u9519\u8bef<\/p>\n
django.core.exceptions.ImproperlyConfigured: mysqlclient 1.3.3 or newer is required; you have 0.7.11.None<\/code><\/pre>\n
\u90a3\u662f\u56e0\u4e3aMySQLclient\u76ee\u524d\u53ea\u652f\u6301\u5230python3.4\uff0c\u5982\u679c\u4f7f\u7528\u7684\u66f4\u9ad8\u7248\u672c\u7684python\uff0c\u9700\u8981\u627e\u5230\u6587\u4ef6C:\\Programs\\Python\\Python36-32\\Lib\\site-packages\\Django-2.0-py3.6.egg\\django\\db\\backends\\mysql\\base.py
\n\u8fd9\u4e2a\u8def\u5f84\u91cc\u7684\u6587\u4ef6(mac\u6216linux\u8bf7\u5728\u7ec8\u7aef\u6267\u884cpip show django\u67e5\u770bdjango\u7684\u5b89\u88c5\u8def\u5f84\uff0c\u627e\u5230base.py\u5373\u53ef)<\/p>\n
# \u6ce8\u91ca\u4e0b\u8ff0\u4e24\u884c\u5185\u5bb9\u5373\u53ef\nif version < (1, 3, 3):\n     raise ImproperlyConfigured("mysqlclient 1.3.3 or newer is required; you have %s" % Database.__version__)<\/code><\/pre>\n
\u6ce8\u610f2\uff1a\u5f53\u6211\u4eec\u76f4\u63a5\u53bb\u6570\u636e\u5e93\u91cc\u67e5\u770b\u751f\u6210\u7684\u8868\u65f6\uff0c\u4f1a\u53d1\u73b0\u6570\u636e\u5e93\u4e2d\u7684\u8868\u4e0eorm\u89c4\u5b9a\u7684\u5e76\u4e0d\u4e00\u81f4\uff0c\u8fd9\u5b8c\u5168\u662f\u6b63\u5e38\u7684\uff0c\u4e8b\u5b9e\u4e0a\uff0corm\u7684\u5b57\u6bb5\u7ea6\u675f\u5c31\u662f\u4e0d\u4f1a\u5168\u90e8\u4f53\u73b0\u5728\u6570\u636e\u5e93\u7684\u8868\u4e2d\uff0c\u6bd4\u5982\u6211\u4eec\u4e3a\u5b57\u6bb5gender\u8bbe\u7f6e\u7684\u9ed8\u8ba4\u503cdefault=1\uff0c\u53bb\u6570\u636e\u5e93\u4e2d\u67e5\u770b\u4f1a\u53d1\u73b0\u8be5\u5b57\u6bb5\u7684default\u90e8\u5206\u4e3anull<\/p>\n
mysql> desc app01_employee; # \u6570\u636e\u5e93\u4e2d\u6807\u7b7e\u524d\u4f1a\u5e26\u6709\u524d\u7f00app01_\n+------------+---------------+------+-----+---------+----------------+\n| Field      | Type          | Null | Key | Default | Extra          |\n+------------+---------------+------+-----+---------+----------------+\n| id         | int(11)       | NO   | PRI | NULL    | auto_increment |\n| name       | varchar(16)   | NO   |     | NULL    |                |\n| gender     | tinyint(1)    | NO   |     | NULL    |                |\n| birth      | date          | NO   |     | NULL    |                |\n| department | varchar(30)   | NO   |     | NULL    |                |\n| salary     | decimal(10,1) | NO   |     | NULL    |                |\n+------------+---------------+------+-----+---------+----------------+<\/code><\/pre>\n
,\u867d\u7136\u6570\u636e\u5e93\u6ca1\u6709\u589e\u52a0\u9ed8\u8ba4\u503c,\u4f46\u662f\u6211\u4eec\u5728\u4f7f\u7528orm\u63d2\u5165\u503c\u65f6\uff0c\u5b8c\u5168\u4e3agender\u5b57\u6bb5\u63d2\u5165\u7a7a\uff0corm\u4f1a\u6309\u7167\u81ea\u5df1\u7684\u7ea6\u675f\u5c06\u7a7a\u8f6c\u6362\u6210\u9ed8\u8ba4\u503c\u540e\uff0c\u518d\u63d0\u4ea4\u7ed9\u6570\u636e\u5e93\u6267\u884c<\/p>\n
2.1.8 \u5728\u8868\u751f\u6210\u4e4b\u540e\uff0c\u5982\u679c\u9700\u8981\u589e\u52a0\u3001\u5220\u9664\u3001\u4fee\u6539\u8868\u4e2d\u5b57\u6bb5\uff0c\u9700\u8981\u8fd9\u4e48\u505a<\/h5>\n
# \u4e00\uff1a\u589e\u52a0\u5b57\u6bb5\n#1.1\u3001\u5728\u6a21\u578b\u7c7bEmployee\u91cc\u76f4\u63a5\u65b0\u589e\u5b57\u6bb5\uff0c\u5f3a\u8c03\uff1a\u5bf9\u4e8eorm\u6765\u8bf4\uff0c\u65b0\u589e\u7684\u5b57\u6bb5\u5fc5\u987b\u7528default\u6307\u5b9a\u9ed8\u8ba4\u503c\npublish = models.CharField(max_length=12,default='\u4eba\u6c11\u51fa\u7248\u793e',null=True)\n#1.2\u3001\u91cd\u65b0\u6267\u884c\u90a3\u4e24\u6761\u6570\u636e\u5e93\u8fc1\u79fb\u547d\u4ee4\n\n# \u4e8c\uff1a\u5220\u9664\u5b57\u6bb5\n#2.1 \u76f4\u63a5\u6ce8\u91ca\u6389\u5b57\u6bb5\n#2.2 \u91cd\u65b0\u6267\u884c\u90a3\u4e24\u6761\u6570\u636e\u5e93\u8fc1\u79fb\u547d\u4ee4\n\n# \u4e09\uff1a\u4fee\u6539\u5b57\u6bb5\n#2.1 \u5c06\u6a21\u578b\u7c7b\u4e2d\u5b57\u6bb5\u4fee\u6539\n#2.2 \u91cd\u65b0\u6267\u884c\u90a3\u4e24\u6761\u6570\u636e\u5e93\u8fc1\u79fb\u547d\u4ee4<\/code><\/pre>\n
2.2 \u6dfb\u52a0\u8bb0\u5f55<\/h2>\n
\u65b9\u5f0f\u4e00\uff1a<\/p>\n
# 1\u3001\u7528\u6a21\u578b\u7c7b\u521b\u5efa\u4e00\u4e2a\u5bf9\u8c61\uff0c\u4e00\u4e2a\u5bf9\u8c61\u5bf9\u5e94\u6570\u636e\u5e93\u8868\u4e2d\u7684\u4e00\u6761\u8bb0\u5f55\nobj = Employee(name="Egon", gender=0, birth='1997-01-27', department="\u8d22\u52a1\u90e8", salary=100.1)\n# 2\u3001\u8c03\u7528\u5bf9\u8c61\u4e0b\u7684save\u65b9\u6cd5\uff0c\u5373\u53ef\u4ee5\u5c06\u4e00\u6761\u8bb0\u5f55\u63d2\u5165\u6570\u636e\u5e93\nobj.save()<\/code><\/pre>\n
\u65b9\u5f0f\u4e8c\uff1a<\/p>\n
# \u6bcf\u4e2a\u6a21\u578b\u8868\u4e0b\u90fd\u6709\u4e00\u4e2aobjects\u7ba1\u7406\u5668\uff0c\u7528\u4e8e\u5bf9\u8be5\u8868\u4e2d\u7684\u8bb0\u5f55\u8fdb\u884c\u589e\u5220\u6539\u67e5\u64cd\u4f5c\uff0c\u5176\u4e2d\u589e\u52a0\u64cd\u4f5c\u5982\u4e0b\u6240\u793a\nobj = Employee.objects.create(name="Egon", gender=0, birth='1997-01-27', department="\u8d22\u52a1\u90e8", salary=100.1)<\/code><\/pre>\n
2.3 \u67e5\u8be2\u8bb0\u5f55<\/h2>\n
2.3.1 \u67e5\u8be2API<\/h3>\n
\u6a21\u578bEmployee\u5bf9\u5e94\u8868app01_employee\uff0c\u8868app01_employee\u4e2d\u7684\u6bcf\u6761\u8bb0\u5f55\u90fd\u5bf9\u5e94\u7c7bEmployee\u7684\u4e00\u4e2a\u5bf9\u8c61\uff0c\u6211\u4eec\u4ee5\u8be5\u8868\u4e3a\u4f8b\uff0c\u6765\u4ecb\u7ecd\u67e5\u8be2API\uff0c\u8bfb\u8005\u53ef\u4ee5\u81ea\u884c\u6dfb\u52a0\u4e0b\u8ff0\u8bb0\u5f55\uff0c\u7136\u540e\u914d\u7f6eurl\u3001\u7f16\u5199\u89c6\u56fe\u6d4b\u8bd5\u4e0b\u8ff0API<\/p>\n
mysql> select * from app01_employee;\n+----+-------+--------+------------+------------+--------+\n| id | name  | gender | birth      | department | salary |\n+----+-------+--------+------------+------------+--------+\n|  1 | Egon  |      0 | 1997-01-27 | \u8d22\u52a1\u90e8     |  100.1 |\n|  2 | Kevin |      1 | 1998-02-27 | \u6280\u672f\u90e8     |   10.1 |\n|  3 | Lili  |      0 | 1990-02-27 | \u8fd0\u8425\u90e8     |   20.1 |\n|  4 | Tom   |      1 | 1991-02-27 | \u8fd0\u8425\u90e8     |   30.1 |\n|  5 | Jack  |      1 | 1992-02-27 | \u6280\u672f\u90e8     |   11.2 |\n|  6 | Robin |      1 | 1988-02-27 | \u6280\u672f\u90e8     |  200.3 |\n|  7 | Rose  |      0 | 1989-02-27 | \u8d22\u52a1\u90e8     |   35.1 |\n|  8 | Egon  |      0 | 1997-01-27 | \u8d22\u52a1\u90e8     |  100.1 |\n|  9 | Egon  |      0 | 1997-01-27 | \u8d22\u52a1\u90e8     |  100.1 |\n+----+-------+--------+------------+------------+--------+<\/code><\/pre>\n
\u6bcf\u4e2a\u6a21\u578b\u8868\u4e0b\u90fd\u6709\u4e00\u4e2aobjects\u7ba1\u7406\u5668,\u7528\u4e8e\u5bf9\u8be5\u8868\u4e2d\u7684\u8bb0\u5f55\u8fdb\u884c\u589e\u5220\u6539\u67e5\u64cd\u4f5c,\u5176\u4e2d\u67e5\u8be2\u64cd\u4f5c\u5982\u4e0b\u6240\u793a<\/p>\n
\"\"<\/div><\/p>\n
Part1\uff1a<\/p>\n
\uff01\uff01\uff01\u5f3a\u8c03\uff01\uff01\uff01\uff1a\u4e0b\u8ff0\u65b9\u6cd5(\u9664\u4e86count\u5916)\u7684\u8fd4\u56de\u503c\u90fd\u662f\u4e00\u4e2a\u6a21\u578b\u7c7bEmployee\u7684\u5bf9\u8c61\uff0c\u4e3a\u4e86\u540e\u7eed\u63cf\u8ff0\u65b9\u4fbf\uff0c\u6211\u4eec\u7edf\u4e00\u5c06\u6a21\u578b\u7c7b\u7684\u5bf9\u8c61\u79f0\u4e3a"\u8bb0\u5f55\u5bf9\u8c61"\uff0c\u6bcf\u4e00\u4e2a\u201d\u8bb0\u5f55\u5bf9\u8c61\u201c\u90fd\u552f\u4e00\u5bf9\u5e94\u8868\u4e2d\u7684\u4e00\u6761\u8bb0\u5f55\uff0c<\/p>\n
# 1. get(**kwargs)\n# 1.1: \u6709\u53c2\uff0c\u53c2\u6570\u4e3a\u7b5b\u9009\u6761\u4ef6\n# 1.2: \u8fd4\u56de\u503c\u4e3a\u4e00\u4e2a\u7b26\u5408\u7b5b\u9009\u6761\u4ef6\u7684\u8bb0\u5f55\u5bf9\u8c61(\u6709\u4e14\u53ea\u6709\u4e00\u4e2a)\uff0c\u5982\u679c\u7b26\u5408\u7b5b\u9009\u6761\u4ef6\u7684\u5bf9\u8c61\u8d85\u8fc7\u4e00\u4e2a\u6216\u8005\u6ca1\u6709\u90fd\u4f1a\u629b\u51fa\u9519\u8bef\u3002\nobj=Employee.objects.get(id=1)\nprint(obj.name,obj.birth,obj.salary) #\u8f93\u51fa\uff1aEgon 1997-01-27 100.1\n\n# 2\u3001first()\n# 2.1\uff1a\u65e0\u53c2\n# 2.2\uff1a\u8fd4\u56de\u67e5\u8be2\u51fa\u7684\u7b2c\u4e00\u4e2a\u8bb0\u5f55\u5bf9\u8c61\nobj=Employee.objects.first() # \u5728\u8868\u6240\u6709\u8bb0\u5f55\u4e2d\u53d6\u7b2c\u4e00\u4e2a\nprint(obj.id,obj.name) # \u8f93\u51fa\uff1a1 Egon\n\n# 3\u3001last()\n# 3.1: \u65e0\u53c2\n# 3.2: \u8fd4\u56de\u67e5\u8be2\u51fa\u7684\u6700\u540e\u4e00\u4e2a\u8bb0\u5f55\u5bf9\u8c61\nobj = Employee.objects.last() # \u5728\u8868\u6240\u6709\u8bb0\u5f55\u4e2d\u53d6\u6700\u540e\u4e00\u4e2a\nprint(obj.id, obj.name)  # \u8f93\u51fa\uff1a9 Egon\n\n# 4\u3001count():\n# 4.1\uff1a\u65e0\u53c2\n# 4.2\uff1a\u8fd4\u56de\u5305\u542b\u8bb0\u5f55\u5bf9\u8c61\u7684\u603b\u6570\u91cf\nres = Employee.objects.count() # \u7edf\u8ba1\u8868\u6240\u6709\u8bb0\u5f55\u7684\u4e2a\u6570\nprint(res) # \u8f93\u51fa\uff1a9\n\n# \u6ce8\u610f\uff1a\u5982\u679c\u6211\u4eec\u76f4\u63a5\u6253\u5370Employee\u7684\u5bf9\u8c61\u5c06\u6ca1\u6709\u4efb\u4f55\u6709\u7528\u7684\u63d0\u793a\u4fe1\u606f\uff0c\u6211\u4eec\u53ef\u4ee5\u5728\u6a21\u578b\u7c7b\u4e2d\u5b9a\u4e49__str__\u6765\u8fdb\u884c\u5b9a\u5236\nclass Employee(models.Model):\n    ......\n    # \u5728\u539f\u6709\u7684\u57fa\u7840\u4e0a\u65b0\u589e\u4ee3\u7801\u5982\u4e0b\n    def __str__(self):\n        return "<%s:%s>" %(self.id,self.name)\n# \u6b64\u65f6\u6211\u4eecprint(obj)\u663e\u793a\u7684\u7ed3\u679c\u5c31\u662f: <\u672c\u6761\u8bb0\u5f55\u4e2did\u5b57\u6bb5\u7684\u503c:\u672c\u6761\u8bb0\u5f55\u4e2dname\u5b57\u6bb5\u7684\u503c><\/code><\/pre>\n
\"\"<\/div><\/p>\n
Part2\uff1a<\/p>\n
\uff01\uff01\uff01\u5f3a\u8c03\uff01\uff01\uff01\uff1a\u4e0b\u8ff0\u65b9\u6cd5\u67e5\u8be2\u7684\u7ed3\u679c\u90fd\u6709\u53ef\u80fd\u5305\u542b\u591a\u4e2a\u8bb0\u5f55\u5bf9\u8c61\uff0c\u4e3a\u4e86\u5b58\u653e\u67e5\u8be2\u51fa\u7684\u591a\u4e2a\u8bb0\u5f55\u5bf9\u8c61\uff0cdjango\u7684ORM\u81ea\u5b9a\u4e49\u4e86\u4e00\u79cd\u6570\u636e\u7c7b\u578bQueryeset\uff0c\u6240\u4ee5\u4e0b\u8ff0\u65b9\u6cd5\u7684\u8fd4\u56de\u503c\u5747\u4e3aQuerySet\u7c7b\u578b\u7684\u5bf9\u8c61\uff0cQuerySet\u5bf9\u8c61\u4e2d\u5305\u542b\u4e86\u67e5\u8be2\u51fa\u7684\u591a\u4e2a\u8bb0\u5f55\u5bf9\u8c61<\/p>\n
# 1\u3001filter(**kwargs):\n# 1.1\uff1a\u6709\u53c2\uff0c\u53c2\u6570\u4e3a\u8fc7\u6ee4\u6761\u4ef6\n# 1.2\uff1a\u8fd4\u56de\u503c\u4e3aQuerySet\u5bf9\u8c61\uff0cQuerySet\u5bf9\u8c61\u4e2d\u5305\u542b\u4e86\u7b26\u5408\u8fc7\u6ee4\u6761\u4ef6\u7684\u591a\u4e2a\u8bb0\u5f55\u5bf9\u8c61\nqueryset_res=Employee.objects.filter(department='\u6280\u672f\u90e8')\n# print(queryset_res) # \u8f93\u51fa\uff1a <QuerySet [<Employee: <2:Kevin>>, <Employee: <5:Jack>>, <Employee: <6:Robin>>]>\n\n# 2\u3001exclude(**kwargs)\n# 2.1: \u6709\u53c2\uff0c\u53c2\u6570\u4e3a\u8fc7\u6ee4\u6761\u4ef6\n# 2.2: \u8fd4\u56de\u503c\u4e3aQuerySet\u5bf9\u8c61\uff0cQuerySet\u5bf9\u8c61\u4e2d\u5305\u542b\u4e86\u4e0d\u7b26\u5408\u8fc7\u6ee4\u6761\u4ef6\u7684\u591a\u4e2a\u8bb0\u5f55\u5bf9\u8c61\nqueryset_res=Employee.objects.exclude(department='\u6280\u672f\u90e8')\n\n# 3\u3001all()\n# 3.1\uff1a\u65e0\u53c2\n# 3.2\uff1a\u8fd4\u56de\u503c\u4e3aQuerySet\u5bf9\u8c61\uff0cQuerySet\u5bf9\u8c61\u4e2d\u5305\u542b\u4e86\u67e5\u8be2\u51fa\u7684\u6240\u6709\u8bb0\u5f55\u5bf9\u8c61\nqueryset_res = Employee.objects.all() # \u67e5\u8be2\u51fa\u8868\u4e2d\u6240\u6709\u7684\u8bb0\u5f55\u5bf9\u8c61\n\n# 4\u3001order_by(*field):\n# 4.1\uff1a\u6709\u53c2\uff0c\u53c2\u6570\u4e3a\u6392\u5e8f\u5b57\u6bb5\uff0c\u53ef\u4ee5\u6307\u5b9a\u591a\u4e2a\u5b57\u6bb5\uff0c\u5728\u5b57\u6bb51\u76f8\u540c\u7684\u60c5\u51b5\u4e0b\uff0c\u53ef\u4ee5\u6309\u7167\u5b57\u6bb52\u8fdb\u884c\u6392\u5e8f\uff0c\u4ee5\u6b64\u7c7b\u63a8\uff0c\u9ed8\u8ba4\u5347\u5e8f\u6392\u5217\uff0c\u5728\u5b57\u6bb5\u524d\u52a0\u6a2a\u6746\u4ee3\u8868\u964d\u5e8f\u6392\uff08\u5982"-id"\uff09\n# 4.2\uff1a\u8fd4\u56de\u503c\u4e3aQuerySet\u5bf9\u8c61\uff0cQuerySet\u5bf9\u8c61\u4e2d\u5305\u542b\u4e86\u6392\u5e8f\u597d\u7684\u8bb0\u5f55\u5bf9\u8c61\nqueryset_res = Employee.objects.order_by("salary","-id") # \u5148\u6309\u7167salary\u5b57\u6bb5\u5347\u5e8f\u6392\uff0c\u5982\u679csalary\u76f8\u540c\u5219\u6309\u7167id\u5b57\u6bb5\u964d\u5e8f\u6392\n\n# 5\u3001values(*field)\n# 5.1\uff1a\u6709\u53c2\uff0c\u53c2\u6570\u4e3a\u5b57\u6bb5\u540d\uff0c\u53ef\u4ee5\u6307\u5b9a\u591a\u4e2a\u5b57\u6bb5\n# 5.2\uff1a\u8fd4\u56de\u503c\u4e3aQuerySet\u5bf9\u8c61\uff0cQuerySet\u5bf9\u8c61\u4e2d\u5305\u542b\u7684\u5e76\u4e0d\u662f\u4e00\u4e2a\u4e2a\u7684\u8bb0\u5f55\u5bf9\u8c61\uff0c\u800c\u4e0a\u591a\u4e2a\u5b57\u5178\uff0c\u5b57\u5178\u7684key\u5373\u6211\u4eec\u4f20\u5165\u7684\u5b57\u6bb5\u540d\nqueryset_res = Employee.objects.values('id','name')\nprint(queryset_res) # \u8f93\u51fa\uff1a<QuerySet [{'id': 1, 'name': 'Egon'}, {'id': 2, 'name': 'Kevin'}, ......]>\nprint(queryset_res[0]['name']) # \u8f93\u51fa\uff1aEgon\n\n# 6\u3001values_list(*field):\n# 6.1\uff1a\u6709\u53c2\uff0c\u53c2\u6570\u4e3a\u5b57\u6bb5\u540d\uff0c\u53ef\u4ee5\u6307\u5b9a\u591a\u4e2a\u5b57\u6bb5\n# 6.2\uff1a\u8fd4\u56de\u503c\u4e3aQuerySet\u5bf9\u8c61\uff0cQuerySet\u5bf9\u8c61\u4e2d\u5305\u542b\u7684\u5e76\u4e0d\u662f\u4e00\u4e2a\u4e2a\u7684\u8bb0\u5f55\u5bf9\u8c61\uff0c\u800c\u4e0a\u591a\u4e2a\u5c0f\u5143\u7ec4\uff0c\u5b57\u5178\u7684key\u5373\u6211\u4eec\u4f20\u5165\u7684\u5b57\u6bb5\u540d\nqueryset_res = Employee.objects.values_list('id','name')\nprint(queryset_res) # \u8f93\u51fa\uff1a<QuerySet [(1, 'Egon'), (2, 'Kevin'),), ......]>\nprint(queryset_res[0][1]) # \u8f93\u51fa\uff1aEgon<\/code><\/pre>\n
Part3\uff1a<\/p>\n
Part2\u4e2d\u6240\u793a\u67e5\u8be2API\u7684\u8fd4\u56de\u503c\u90fd\u662fQuerySet\u7c7b\u578b\u7684\u5bf9\u8c61\uff0cQuerySet\u7c7b\u578b\u662fdjango ORM\u81ea\u5b9a\u4e49\u7684\u4e00\u79cd\u6570\u636e\u7c7b\u578b\uff0c\u4e13\u95e8\u7528\u6765\u5b58\u653e\u67e5\u8be2\u51fa\u7684\u591a\u4e2a\u8bb0\u5f55\u5bf9\u8c61\uff0c\u8be5\u7c7b\u578b\u7684\u7279\u6b8a\u4e4b\u5904\u5728\u4e8e
\n1\u3001queryset\u7c7b\u578b\u7c7b\u4f3c\u4e8epython\u4e2d\u7684\u5217\u8868\uff0c\u652f\u6301\u7d22\u5f15\u64cd\u4f5c<\/p>\n
# \u8fc7\u6ee4\u51fa\u7b26\u5408\u6761\u4ef6\u7684\u591a\u4e2a\u8bb0\u5f55\u5bf9\u8c61\uff0c\u7136\u540e\u5b58\u653e\u5230QuerySet\u5bf9\u8c61\u4e2d\nqueryset_res=Employee.objects.filter(department='\u6280\u672f\u90e8') \n# \u6309\u7167\u7d22\u5f15\u4eceQuerySet\u5bf9\u8c61\u4e2d\u53d6\u51fa\u7b2c\u4e00\u4e2a\u8bb0\u5f55\u5bf9\u8c61\nobj=queryset_res[0]\nprint(obj.name,obj.birth,obj.salary)<\/code><\/pre>\n
2\u3001\u7ba1\u7406\u5668objects\u4e0b\u7684\u65b9\u6cd5queryset\u4e0b\u540c\u6837\u53ef\u4ee5\u8c03\u7528\uff0c\u5e76\u4e14django\u7684ORM\u652f\u6301\u94fe\u5f0f\u64cd\u4f5c\uff0c\u4e8e\u662f\u6211\u4eec\u53ef\u4ee5\u50cf\u4e0b\u9762\u8fd9\u6837\u4f7f\u7528<\/p>\n
# \u7b80\u5355\u793a\u8303\uff1a\nres=Employee.objects.filter(gender=1).order_by('-id').values_list('id','name')\nprint(res) # \u8f93\u51fa\uff1a<QuerySet [(6, 'Robin'), (5, 'Jack'), (4, 'Tom'), (2, 'Kevin')]><\/code><\/pre>\n
Part4\uff1a<\/p>\n
\u5176\u4ed6\u67e5\u8be2API<\/p>\n
# 1\u3001reverse():\n# 1.1\uff1a\u65e0\u53c2\n# 1.2\uff1a\u5bf9\u6392\u5e8f\u7684\u7ed3\u679c\u53d6\u53cd\uff0c\u8fd4\u56de\u503c\u4e3aQuerySet\u5bf9\u8c61\nqueryset_res = Employee.objects.order_by("salary", "-id").reverse()\n\n# 2\u3001exists():\n# 2.1\uff1a\u65e0\u53c2\n# 2.2\uff1a\u8fd4\u56de\u503c\u4e3a\u5e03\u5c14\u503c\uff0c\u5982\u679cQuerySet\u5305\u542b\u6570\u636e\uff0c\u5c31\u8fd4\u56deTrue\uff0c\u5426\u5219\u8fd4\u56deFalse\nres = Employee.objects.filter(id=100).exists()\nprint(res)  # \u8f93\u51fa\uff1aFalse\n\n# 3\u3001distinct():\n# 3.1\uff1a\u5982\u679c\u4f7f\u7528\u7684\u662fMysql\u6570\u636e\u5e93,\u90a3\u4e48distinct()\u65e0\u9700\u4f20\u5165\u4efb\u4f55\u53c2\u6570\n# 3.2\uff1a\u4ecevalues\u6216values_list\u7684\u8fd4\u56de\u7ed3\u679c\u4e2d\u5254\u9664\u91cd\u590d\u7684\u8bb0\u5f55\u5bf9\u8c61\uff0c\u8fd4\u56de\u503c\u4e3aQuerySet\u5bf9\u8c61\nres = Employee.objects.filter(name='Egon').values('name', 'salary').distinct()\nprint(res) # \u8f93\u51fa\uff1a<QuerySet [{'name': 'Egon', 'salary': Decimal('100.1')}]>\n\nres1 = Employee.objects.filter(name='Egon').values_list('name', 'salary').distinct()\nprint(res1) # \u8f93\u51fa\uff1a<QuerySet [('Egon', Decimal('100.1'))]><\/code><\/pre>\n
2.3.2 \u57fa\u4e8e\u53cc\u4e0b\u5212\u7ebf\u7684\u6a21\u7cca\u67e5\u8be2<\/h3>\n
\"\"<\/div><\/p>\n
\"\"<\/div><\/p>\n
2.3.3 F\u4e0eQ\u67e5\u8be2<\/h3>\n
F\u67e5\u8be2<\/h4>\n
\u5728\u4e0a\u9762\u6240\u6709\u7684\u4f8b\u5b50\u4e2d\uff0c\u6211\u4eec\u5728\u8fdb\u884c\u6761\u4ef6\u8fc7\u6ee4\u65f6\uff0c\u90fd\u53ea\u662f\u7528\u67d0\u4e2a\u5b57\u6bb5\u4e0e\u67d0\u4e2a\u5177\u4f53\u7684\u503c\u505a\u6bd4\u8f83\u3002\u5982\u679c\u6211\u4eec\u8981\u5bf9\u4e24\u4e2a\u5b57\u6bb5\u7684\u503c\u505a\u6bd4\u8f83\uff0c\u90a3\u8be5\u600e\u4e48\u505a\u5462\uff1f<\/p>\n
Django \u63d0\u4f9b F() \u6765\u505a\u8fd9\u6837\u7684\u6bd4\u8f83\u3002F() \u7684\u5b9e\u4f8b\u53ef\u4ee5\u5728\u67e5\u8be2\u4e2d\u5f15\u7528\u5b57\u6bb5\uff0c\u6765\u6bd4\u8f83\u4e24\u4e2a\u4e0d\u540c\u5b57\u6bb5\u7684\u503c\uff0c\u5982\u4e0b<\/p>\n
# \u4e00\u5f20\u4e66\u7c4d\u8868\u4e2d\u5305\u542b\u5b57\u6bb5\uff1a\u8bc4\u8bba\u6570commentNum\u3001\u6536\u85cf\u6570keepNum\uff0c\u8981\u6c42\u67e5\u8be2\uff1a\u8bc4\u8bba\u6570\u5927\u4e8e\u6536\u85cf\u6570\u7684\u4e66\u7c4d\nfrom django.db.models import F\nBook.objects.filter(commnetNum__lt=F('keepNum'))<\/code><\/pre>\n
Django \u652f\u6301 F() \u5bf9\u8c61\u4e4b\u95f4\u4ee5\u53ca F() \u5bf9\u8c61\u548c\u5e38\u6570\u4e4b\u95f4\u7684\u52a0\u51cf\u4e58\u9664\u548c\u53d6\u6a21\u7684\u64cd\u4f5c<\/p>\n
# \u67e5\u8be2\u8bc4\u8bba\u6570\u5927\u4e8e\u6536\u85cf\u65702\u500d\u7684\u4e66\u7c4d\nfrom django.db.models import F\nBook.objects.filter(commnetNum__lt=F('keepNum')*2)<\/code><\/pre>\n
\u4fee\u6539\u64cd\u4f5c\u4e5f\u53ef\u4ee5\u4f7f\u7528F\u51fd\u6570,\u6bd4\u5982\u5c06\u6bcf\u4e00\u672c\u4e66\u7684\u4ef7\u683c\u63d0\u9ad830\u5143\uff1a<\/p>\n
Book.objects.all().update(price=F("price")+30)\u3000<\/code><\/pre>\n
\u66f4\u65b0\u5b57\u6bb5\u7b49\u4e8e\u5b57\u6bb5\u672c\u8eab\u518d\u62fc\u63a5\u4e00\u4e2a\u5b57\u7b26\u4e32\u5e94\u8be5\u8fd9\u6837\u505a<\/p>\n
from django.db.models.functions import Concat\nfrom django.db.models import Value\n\nEmployee.objects.filter(nid__lte=3).update(name=Concat(F('name'),Value('_sb')))<\/code><\/pre>\n
Q\u67e5\u8be2<\/h4>\n
\"\"<\/div><\/p>\n
filter()<\/code> \u7b49\u65b9\u6cd5\u4e2d\u9017\u53f7\u5206\u9694\u5f00\u7684\u591a\u4e2a\u5173\u952e\u5b57\u53c2\u6570\u90fd\u662f\u903b\u8f91\u4e0e(AND) \u7684\u5173\u7cfb\u3002 \u5982\u679c\u6211\u4eec\u9700\u8981\u4f7f\u7528\u903b\u8f91\u6216(OR)\u6765\u8fde\u63a5\u591a\u4e2a\u6761\u4ef6\uff0c\u5c31\u7528\u5230\u4e86Django\u7684Q\u5bf9\u8c61<\/p>\n
\u53ef\u4ee5\u5c06\u6761\u4ef6\u4f20\u7ed9\u7c7bQ\u6765\u5b9e\u4f8b\u5316\u51fa\u4e00\u4e2a\u5bf9\u8c61\uff0cQ\u7684\u5bf9\u8c61\u53ef\u4ee5\u4f7f\u7528&<\/code> \u548c|<\/code> \u64cd\u4f5c\u7b26\u7ec4\u5408\u8d77\u6765\uff0c&\u7b49\u540c\u4e8eand\uff0c|\u7b49\u540c\u4e8eor<\/p>\n
from django.db.models import Q\nEmployee.objects.filter(Q(id__gt=5) | Q(name="Egon"))\n\n# \u7b49\u540c\u4e8esql\uff1aselect * from app01_employee where id < 5 or name = 'Egon';<\/code><\/pre>\n
Q<\/code> \u5bf9\u8c61\u53ef\u4ee5\u4f7f\u7528~<\/code> \u64cd\u4f5c\u7b26\u53d6\u53cd\uff0c\u76f8\u5f53\u4e8eNOT<\/p>\n
from django.db.models import Q\nEmployee.objects.filter(~Q(id__gt=5) | Q(name="Egon"))\n\n# \u7b49\u540c\u4e8esql\uff1aselect * from app01_employee where not (id < 5) or name = 'Egon';<\/code><\/pre>\n
\u5f53\u6211\u4eec\u7684\u8fc7\u6ee4\u6761\u4ef6\u4e2d\u65e2\u6709or\u53c8\u6709and\uff0c\u5219\u9700\u8981\u6df7\u7528Q\u5bf9\u8c61\u4e0e\u5173\u952e\u5b57\u53c2\u6570\uff0c\u4f46Q<\/code> \u5bf9\u8c61\u5fc5\u987b\u4f4d\u4e8e\u6240\u6709\u5173\u952e\u5b57\u53c2\u6570\u7684\u524d\u9762<\/p>\n
from django.db.models import Q\nEmployee.objects.filter(Q(id__gt=5) | Q(name="Egon"),salary__lt=100)\n\n# \u7b49\u540c\u4e8esql\uff1aselect * from app01_employee where (id < 5 or name = 'Egon') and salary < 100;<\/code><\/pre>\n
\"\"<\/div><\/p>\n
2.3.4 \u805a\u5408\u67e5\u8be2<\/h3>\n
\u805a\u5408\u67e5\u8be2aggregate()\u662f\u628a\u6240\u6709\u67e5\u8be2\u51fa\u7684\u8bb0\u5f55\u5bf9\u8c61\u6574\u4f53\u5f53\u505a\u4e00\u4e2a\u7ec4\uff0c\u6211\u4eec\u53ef\u4ee5\u642d\u914d\u805a\u5408\u51fd\u6570\u6765\u5bf9\u6574\u4f53\u8fdb\u884c\u4e00\u4e2a\u805a\u5408\u64cd\u4f5c<\/p>\n
from django.db.models import Avg, Max, Sum, Min, Max, Count # \u5bfc\u5165\u805a\u5408\u51fd\u6570\n\n# 1. \u8c03\u7528objects\u4e0b\u7684aggregate()\u65b9\u6cd5\uff0c\u4f1a\u628a\u8868\u4e2d\u6240\u6709\u8bb0\u5f55\u5bf9\u8c61\u6574\u4f53\u5f53\u505a\u4e00\u7ec4\u8fdb\u884c\u805a\u5408\nres1=Employee.objects.aggregate(Avg("salary")) # select avg(salary) as salary__avg from app01_employee;\nprint(res1) # \u8f93\u51fa\uff1a{'salary__avg': 70.73}\n\n# 2\u3001aggregate()\u4f1a\u628aQuerySet\u5bf9\u8c61\u4e2d\u5305\u542b\u7684\u6240\u6709\u8bb0\u5f55\u5bf9\u8c61\u5f53\u6210\u4e00\u7ec4\u8fdb\u884c\u805a\u5408\nres2=Employee.objects.all().aggregate(Avg("salary")) # select avg(salary) as salary__avg from app01_employee;\nprint(res2) # \u8f93\u51fa\uff1a{'salary__avg': 70.73}\n\nres3=Employee.objects.filter(id__gt=3).aggregate(Avg("salary")) # select avg(salary) as salary__avg from app01_employee where id > 3;\nprint(res3) # \u8f93\u51fa\uff1a{'salary__avg': 71.0}<\/code><\/pre>\n
aggregate()\u7684\u8fd4\u56de\u503c\u4e3a\u5b57\u5178\u7c7b\u578b\uff0c\u5b57\u5178\u7684key\u662f\u7531\u201d\u805a\u5408\u5b57\u6bb5\u7684\u540d\u79f0___\u805a\u5408\u51fd\u6570\u7684\u540d\u79f0\u201d\u5408\u6210\u7684,\u4f8b\u5982<\/p>\n
Avg("salary") \u5408\u6210\u7684\u540d\u5b57\u4e3a 'salary__avg'<\/code><\/pre>\n
\u82e5\u6211\u4eec\u60f3\u5b9a\u5236\u5b57\u5178\u7684key\u540d\uff0c\u6211\u4eec\u53ef\u4ee5\u6307\u5b9a\u5173\u952e\u53c2\u6570\uff0c\u5982\u4e0b<\/p>\n
res1=Employee.objects.all().aggregate(avg_sal=Avg('salary')) # select avg(salary) as avg_sal from app01_employee;\n\nprint(res1) # \u8f93\u51fa\uff1a{'avg_sal': 70.73} # \u5173\u952e\u5b57\u53c2\u6570\u540d\u5c31\u4f1a\u88ab\u5f53\u505a\u5b57\u5178\u7684key<\/code><\/pre>\n
\u5982\u679c\u6211\u4eec\u60f3\u5f97\u5230\u591a\u4e2a\u805a\u5408\u7ed3\u679c\uff0c\u90a3\u5c31\u9700\u8981\u4e3aaggregate\u4f20\u5165\u591a\u4e2a\u53c2\u6570<\/p>\n
res1=Employee.objects.all().aggregate(nums=Count('id'),avg_sal=Avg('salary'),max_sal=Max('salary')) \n# \u76f8\u5f53\u4e8eSQL\uff1aselect count(id) as nums,avg(salary) as avg_sal,max(salary) as max_sal from app01_employee;\n\nprint(res1) # \u8f93\u51fa\uff1a{'nums': 10, 'avg_sal': 70.73, 'max_sal': Decimal('200.3')}<\/code><\/pre>\n
\"\"<\/div><\/p>\n
2.3.5 \u5206\u7ec4\u67e5\u8be2<\/h3>\n
\u5206\u7ec4\u67e5\u8be2annotate()\u76f8\u5f53\u4e8esql\u8bed\u53e5\u4e2d\u7684group by\uff0c\u662f\u5728\u5206\u7ec4\u540e\uff0c\u5bf9\u6bcf\u4e2a\u7ec4\u8fdb\u884c\u5355\u72ec\u7684\u805a\u5408\uff0c\u9700\u8981\u5f3a\u8c03\u7684\u662f\uff0c\u5728\u8fdb\u884c\u5355\u8868\u67e5\u8be2\u65f6\uff0cannotate()\u5fc5\u987b\u642d\u914dvalues()\u4f7f\u7528\uff1avalues("\u5206\u7ec4\u5b57\u6bb5").annotate(\u805a\u5408\u51fd\u6570)\uff0c\u5982\u4e0b<\/p>\n
# \u8868\u4e2d\u8bb0\u5f55\nmysql> select * from app01_employee;\n+----+-------+--------+------------+------------+--------+\n| id | name  | gender | birth      | department | salary |\n+----+-------+--------+------------+------------+--------+\n|  1 | Egon  |      0 | 1997-01-27 | \u8d22\u52a1\u90e8     |  100.1 |\n|  2 | Kevin |      1 | 1998-02-27 | \u6280\u672f\u90e8     |   10.1 |\n|  3 | Lili  |      0 | 1990-02-27 | \u8fd0\u8425\u90e8     |   20.1 |\n|  4 | Tom   |      1 | 1991-02-27 | \u8fd0\u8425\u90e8     |   30.1 |\n|  5 | Jack  |      1 | 1992-02-27 | \u6280\u672f\u90e8     |   11.2 |\n|  6 | Robin |      1 | 1988-02-27 | \u6280\u672f\u90e8     |  200.3 |\n|  7 | Rose  |      0 | 1989-02-27 | \u8d22\u52a1\u90e8     |   35.1 |\n+----+-------+--------+------------+------------+--------+\n\n# \u67e5\u8be2\u6bcf\u4e2a\u90e8\u95e8\u4e0b\u7684\u5458\u5de5\u6570\nres=Employee.objects.values('department').annotate(num=Count('id')) \n# \u76f8\u5f53\u4e8esql\uff1a\n# select department,count(id) as num from app01_employee group by department;\n\nprint(res) \n# \u8f93\u51fa\uff1a<QuerySet [{'department': '\u8d22\u52a1\u90e8', 'num': 2}, {'department': '\u6280\u672f\u90e8', 'num': 3}, {'department': '\u8fd0\u8425\u90e8', 'num': 2}]>\n<\/code><\/pre>\n
\u8ddf\u5728annotate\u524d\u7684values\u65b9\u6cd5\uff0c\u662f\u7528\u6765\u6307\u5b9a\u5206\u7ec4\u5b57\u6bb5\uff0c\u5373group by\u540e\u7684\u5b57\u6bb5\uff0c\u800c\u8ddf\u5728annotate\u540e\u7684values\u65b9\u6cd5\uff0c\u5219\u662f\u7528\u6765\u6307\u5b9a\u5206\u7ec4\u540e\u8981\u67e5\u8be2\u7684\u5b57\u6bb5\uff0c\u5373select \u540e\u8ddf\u7684\u5b57\u6bb5<\/p>\n
res=Employee.objects.values('department').annotate(num=Count('id')).values('num')\n# \u76f8\u5f53\u4e8esql\uff1a\n# select count(id) as num from app01_employee group by department;\n\nprint(res)\n# \u8f93\u51fa\uff1a<QuerySet [{'num': 2}, {'num': 3}, {'num': 2}]><\/code><\/pre>\n
\u8ddf\u5728annotate\u524d\u7684filter\u65b9\u6cd5\u8868\u793awhere\u6761\u4ef6\uff0c\u8ddf\u5728annotate\u540e\u7684filter\u65b9\u6cd5\u8868\u793ahaving\u6761\u4ef6\uff0c\u5982\u4e0b<\/p>\n
# \u67e5\u8be2\u7537\u5458\u5de5\u6570\u8d85\u8fc72\u4eba\u7684\u90e8\u95e8\u540d\nres=Employee.objects.filter(gender=1).values('department').annotate(male_count=Count("id")).filter(male_count__gt=2).values('department')\n\nprint(res) # \u8f93\u51fa\uff1a<QuerySet [{'department': '\u6280\u672f\u90e8'}]>\n\n# \u89e3\u6790\uff1a\n# 1\u3001\u8ddf\u5728annotate\u524d\u7684filter(gender=1) \u76f8\u5f53\u4e8e where gender = 1\uff0c\u5148\u8fc7\u6ee4\u51fa\u6240\u6709\u7537\u5458\u5de5\u4fe1\u606f\n# 2\u3001values('department').annotate(male_count=Count("id")) \u76f8\u5f53\u4e8egroup by department\uff0c\u5bf9\u8fc7\u6ee4\u51fa\u7684\u7537\u5458\u5de5\u6309\u7167\u90e8\u95e8\u5206\u7ec4\uff0c\u7136\u540e\u805a\u5408\u51fa\u6bcf\u4e2a\u90e8\u95e8\u5185\u7684\u7537\u5458\u5de5\u6570\u8d4b\u503c\u7ed9\u5b57\u6bb5male_count\n# 3\u3001\u8ddf\u5728annotate\u540e\u7684filter(male_count__gt=2) \u76f8\u5f53\u4e8e having male_count > 2,\u4f1a\u8fc7\u6ee4\u51fa\u7537\u5458\u5de5\u6570\u8d85\u8fc72\u4eba\u7684\u90e8\u95e8\n# 4\u3001\u6700\u540e\u7684values('department')\u4ee3\u8868\u4ece\u6700\u7ec8\u7684\u7ed3\u679c\u4e2d\u53ea\u53d6\u90e8\u95e8\u540d<\/code><\/pre>\n
\u603b\u7ed3\uff1a<\/p>\n
1\u3001values()\u5728annotate()\u524d\u8868\u793agroup by\u7684\u5b57\u6bb5\uff0c\u5728\u540e\u8868\u793a\u53d6\u503c\n1\u3001filter()\u5728annotate()\u524d\u8868\u793awhere\u6761\u4ef6\uff0c\u5728\u540e\u8868\u793ahaving<\/code><\/pre>\n
\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u5982\u679c\u6211\u4eec\u5728annotate\u524d\u6ca1\u6709\u6307\u5b9avalues()\uff0c\u90a3\u9ed8\u8ba4\u7528\u8868\u4e2d\u7684id\u5b57\u6bb5\u4f5c\u4e3a\u5206\u7ec4\u4f9d\u636e\uff0c\u800cid\u5404\u4e0d\u76f8\u540c\uff0c\u5982\u6b64\u5206\u7ec4\u662f\u6ca1\u6709\u610f\u4e49\u7684\uff0c\u5982\u4e0b<\/p>\n
res=Employee.objects.annotate(Count('name')) # \u6bcf\u6761\u8bb0\u5f55\u90fd\u662f\u4e00\u4e2a\u5206\u7ec4\nres=Employee.objects.all().annotate(Count('name')) # \u540c\u4e0a<\/code><\/pre>\n
2.4 \u4fee\u6539\u8bb0\u5f55<\/h2>\n
2.5.1 \u76f4\u63a5\u4fee\u6539\u5355\u6761\u8bb0\u5f55<\/h3>\n
\u53ef\u4ee5\u4fee\u6539\u8bb0\u5f55\u5bf9\u8c61\u5c5e\u6027\u7684\u503c\uff0c\u7136\u540e\u6267\u884csave\u65b9\u6cd5\u4ece\u800c\u5b8c\u6210\u5bf9\u5355\u6761\u8bb0\u5f55\u7684\u76f4\u63a5\u4fee\u6539<\/p>\n
# 1\u3001\u83b7\u53d6\u8bb0\u5f55\u5bf9\u8c61\nobj=Employee.objects.filter(name='Egon')[0]\n# 2\u3001\u4fee\u6539\u8bb0\u5f55\u5bf9\u8c61\u5c5e\u6027\u7684\u503c\nobj.name='EGON'\nobj.gender=1\n# 3\u3001\u91cd\u65b0\u4fdd\u5b58\nobj.save()<\/code><\/pre>\n
2.5.2 \u4fee\u6539QuerySet\u4e2d\u7684\u6240\u6709\u8bb0\u5f55\u5bf9\u8c61<\/h3>\n
QuerySet\u5bf9\u8c61\u4e0b\u7684update()\u65b9\u6cd5\u53ef\u4ee5\u66f4QuerySet\u4e2d\u5305\u542b\u7684\u6240\u6709\u5bf9\u8c61\uff0c\u8be5\u65b9\u6cd5\u4f1a\u8fd4\u56de\u4e00\u4e2a\u6574\u578b\u6570\u503c\uff0c\u8868\u793a\u53d7\u5f71\u54cd\u7684\u8bb0\u5f55\u6761\u6570\uff08\u76f8\u5f53\u4e8esql\u8bed\u53e5\u6267\u884c\u7ed3\u679c\u7684rows\uff09<\/p>\n
queryset_obj=Employee.objects.filter(id__gt=5)\nrows=queryset_obj.update(name='EGON',gender=1)<\/code><\/pre>\n
2.5 \u5220\u9664\u8bb0\u5f55<\/h2>\n
\"\"<\/div><\/p>\n
2.5.1 \u76f4\u63a5\u5220\u9664\u5355\u6761\u8bb0\u5f55<\/h3>\n
\u53ef\u4ee5\u76f4\u63a5\u8c03\u7528\u8bb0\u5f55\u5bf9\u8c61\u4e0b\u7684delete\u65b9\u6cd5\uff0c\u8be5\u65b9\u6cd5\u8fd0\u884c\u65f6\u7acb\u5373\u5220\u9664\u672c\u6761\u8bb0\u5f55\u800c\u4e0d\u8fd4\u56de\u4efb\u4f55\u503c,\u5982\u4e0b<\/p>\n
obj=Employee.objects.first()\nobj.delete()<\/code><\/pre>\n
2.5.2 \u5220\u9664QuerySet\u4e2d\u7684\u6240\u6709\u8bb0\u5f55\u5bf9\u8c61<\/h3>\n
\u6bcf\u4e2a QuerySet\u4e0b\u4e5f\u90fd\u6709\u4e00\u4e2a delete() \u65b9\u6cd5\uff0c\u5b83\u4e00\u6b21\u6027\u5220\u9664 QuerySet \u4e2d\u6240\u6709\u7684\u5bf9\u8c61\uff08\u5982\u679cQuerySet\u5bf9\u8c61\u4e2d\u53ea\u6709\u4e00\u4e2a\u8bb0\u5f55\u5bf9\u8c61\uff0c\u90a3\u4e5f\u5c31\u53ea\u5220\u4e00\u6761\uff09\uff0c\u5982\u4e0b<\/p>\n
queryset_obj=Employee.objects.filter(id__gt=5)\nrows=queryset_obj.delete()<\/code><\/pre>\n
\u9700\u8981\u5f3a\u8c03\u7684\u662f\u7ba1\u7406objects\u4e0b\u5e76\u6ca1\u6709delete\u65b9\u6cd5\uff0c\u8fd9\u662f\u4e00\u79cd\u4fdd\u62a4\u673a\u5236\uff0c\u662f\u4e3a\u4e86\u907f\u514d\u610f\u5916\u5730\u8c03\u7528 Employee.objects.delete() \u65b9\u6cd5\u5bfc\u81f4\u6240\u6709\u7684\u8bb0\u5f55\u88ab\u8bef\u5220\u9664\u4ece\u800c\u8dd1\u8def\u3002\u4f46\u5982\u679c\u4f60\u786e\u8ba4\u8981\u5220\u9664\u6240\u6709\u7684\u8bb0\u5f55\uff0c\u90a3\u4e48\u4f60\u5fc5\u987b\u663e\u5f0f\u5730\u8c03\u7528\u7ba1\u7406\u5668\u4e0b\u7684all\u65b9\u6cd5\uff0c\u62ff\u5230\u4e00\u4e2aQuerySet\u5bf9\u8c61\u540e\u624d\u80fd\u8c03\u7528delete\u65b9\u6cd5\u5220\u9664\u6240\u6709<\/p>\n
Employee.objects.all().delete()<\/code><\/pre>\n
\"\"<\/div><\/p>\n","protected":false},"excerpt":{"rendered":"
Django\u4e4b\u6a21\u578b\u5c42\u7b2c\u4e00\u7bc7\uff1a\u5355\u8868\u64cd\u4f5c \u4e00 ORM\u7b80\u4ecb \u200b \u6211\u4eec\u5728\u4f7f\u7528Django\u6846\u67b6\u5f00\u53d1web\u5e94\u7528\u7684\u8fc7\u7a0b\u4e2d\uff0c\u4e0d […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[385,389],"tags":[],"_links":{"self":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts\/5794"}],"collection":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5794"}],"version-history":[{"count":0,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts\/5794\/revisions"}],"wp:attachment":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5794"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5794"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5794"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}