7.连表操作

Posted 2020-11-02 Outback

利用双下划线和 _set 将表之间的操作连接起来

一、数据表结构

from django.db import models

   

class UserProfile(models.Model):

        user_info = models.OneToOneField(‘UserInfo‘,on_delete=None)

        username = models.CharField(max_length=64)

        password = models.CharField(max_length=64)

   

        def __str__(self):

                return self.username

   

class UserInfo(models.Model):

        user_type_choice = (

                (0, u‘普通用户‘),

                (1, u‘高级用户‘),

        )

        user_type = models.IntegerField(choices=user_type_choice)

        name = models.CharField(max_length=32)

        email = models.CharField(max_length=32)

        address = models.CharField(max_length=128)

   

        def __str__(self):

                return self.name

   

class UserGroup(models.Model):

        caption = models.CharField(max_length=64)

   

        user_info = models.ManyToManyField(‘UserInfo‘)

   

        def __str__(self):

                return self.caption

   

class Host(models.Model):

        hostname = models.CharField(max_length=64)

        ip = models.GenericIPAddressField()

        user_group = models.ForeignKey(‘UserGroup‘)

   

        def __str__(self):

                return self.hostname

   

二、一对一查询

user_info_obj = models.UserInfo.objects.filter(id=1).first()

print(user_info_obj.user_type)

print(user_info_obj.get_user_type_display())

print(user_info_obj.userprofile.password) #这里userprofile是小写。因为在数据库中全部是小写

   

user_info_obj = models.UserInfo.objects.filter(id=1).values(‘email‘, ‘userprofile__username‘).first()

print(user_info_obj.keys())

print(user_info_obj.values())

   

三、一对多查询

类似一对一
1、搜索条件使用 __ 连接
2、获取值时使用 . 连接

   

四、多对多操作