{"data":{"markdownRemark":{"html":"

Field types

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AutoField 字段自增

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BooleanField 布尔字段

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CharField 字符串字段

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DateField 日期字段

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DateTimeField 时间日期字段

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DecimalField Decimal字段

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EmailField 邮箱字段

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FilePathField 文件路径字段

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FloatField 浮点字段

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IntegerField 整数字段

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IPAddressField ip地址字段

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GenericIPAddressField ip地址字段

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SlugField Slug字段

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TextField 文本字段

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TimeField 时间字段

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URLField url字段

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BinaryField 二进制字段

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UUIDField uuid字段

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field options

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verbose_name from表单显示名称

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primary_key 主键

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max_length 最大长度

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blank 是否为null

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default 默认值

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choices 选择项

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db_index 是否创建索引

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db_column 列名

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unique 是否唯一

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editable from表单可编辑

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from django.db import models\nimport datetime\nimport uuid\nfrom django.utils import timezone\n\nclass Person(models.Model):\n    id = models.UUIDField( primary_key=True, default=uuid.uuid1())\n    # id = models.AutoField(primary_key=True)\n    gender = models.CharField(blank=False, db_column=\"gender\", max_length=250, choices=(\n        ('female', '男'),\n        ('male', '女'),\n    ),\n                              db_index=True, default=\"默认值\", editable=False,\n                              error_messages={'blank': 'INVALID!!11', 'null': 'NULL11!'},\n                              help_text=\"Please use the following format: <em>YYYY-MM-DD</em>.\",\n                              primary_key=False, unique=False\n                              )\n    age = models.IntegerField(default=0)\n    email = models.EmailField(default=\"kastrcn@outlook.com\")\n    birthday = models.DateField(default=datetime.date.today)\n    create_at = models.DateTimeField(verbose_name=\"创建时间\", default=timezone.now)\n    class Meta:\n        db_table = 'user'\n        # abstract = True\n        ordering = ['-gender']
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表关系

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一对多关联

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class BookInfo(models.Model):\n    pass\n#定义英雄模型类HeroInfo\nclass HeroInfo(models.Model):\n    hbook = models.ForeignKey('BookInfo')#英雄与图书表的关系为一对多，所以属性定义在英雄模型类中
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一对一关联

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class Place(models.Model):\n    pass\nclass Restaurant(models.Model):\n    place = models.OneToOneField(Place, on_delete=models.CASCADE,primary_key=True)
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多对多关联

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class TypeInfo(models.Model):\n\tpass\nclass NewsInfo(models.Model):\n  ntype = models.ManyToManyField('TypeInfo')
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自关联

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class AreaInfo(models.Model):\n    atitle=models.CharField(max_length=30)#名称\n    aParent=models.ForeignKey('self',null=True,blank=True)#关系
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QuerySets

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查询最后一条记录 返回model对象\nRole.objects.last()

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查询第一条记录 返回model对象\nRole.objects.first()

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获取主键为1的记录 返回model对象\nRole.objects.get(pk=1)

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查询id等于1的记录 返回model对象集合\nRole.objects.filter(id=1)

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查询id等于1 name等于默认角色的记录 返回model对象集合\nRole.objects.filter(id=1, name="默认角色")

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查询id等于1 name等于默认角色的记录 返回键值对集合\nRole.objects.filter(id=1, name="默认角色").values()

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查询id等于1 name等于默认角色的记录 返回只包含id的键值对集合\nRole.objects.filter(id=1, name="默认角色").values('id')

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查询Role所有id 返回id元组集合\nRole.objects.values_list("id")

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查询Role所有id 返回id元组集合 以id倒叙排序\nRole.objects.values_list("id").order_by('-id')

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查询Role所有id 根据id去重 返回id元组集合\nRole.objects.distinct("id").values_list("id")

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查询Role所有id 根据id去重 返回id元组集合\nRole.objects.values_list("id").order_by('-id').distinct('id')

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values和values_list

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>>> Role.objects.values("id","name")\n<QuerySet [{'id': 1, 'name': '默认角色'}, {'id': 2, 'name': '默认角色'}, {'id': 3, 'name': '默认角色'}, {'id': 4, 'name': '默认角色'}]>\nRole.objects.values("id","name")[0]["id"]\n<class 'dict'>\n\n\n>>> Role.objects.values_list("id","name")\n<QuerySet [(1, '默认角色'), (2, '默认角色'), (3, '默认角色'), (4, '默认角色')]>\nRole.objects.values_list("id", "name")[0][0]\n<class 'tuple'>
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QuerySet转SQL

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print(Role.objects.values_list(\"id\", \"name\").query)\nstr(Role.objects.values_list(\"id\", \"name\").query)\n# SELECT \"app_role\".\"id\", \"app_role\".\"name\" FROM \"app_role\"
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flat字段 多个字段无效

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>>> Entry.objects.values_list('id').order_by('id')\n<QuerySet[(1,), (2,), (3,), ...]>\n\n>>> Entry.objects.values_list('id', flat=True).order_by('id')\n<QuerySet [1, 2, 3, ...]>
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json序列化

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from django.core import serializers\nserialized_obj = serializers.serialize('json', [user, ])
","frontmatter":{"title":"Object-relational mapper"}}},"pageContext":{"slug":"/build/repo/Django/1、ORM/"}}