ORM操作：
class UserInfo(models.Model):
username = models.CharField(max_length=32)
password = models.CharField(max_length=64)
dp = models.ForeignKey(to='DePart',to_field='id')
# depart = models.ForeignKey('DePart')
class DePart(models.Model):
title = models.CharField(max_length=16)
# ForeignKey查询
# 正向跨表查询
# 1.对象
# q = models.UserInfo.objects.all()
# for row in q:
# print(row.username,row.password,row.dp_id,row.dp.id,row.db.title)
# 2.字典
# q = models.UserInfo.objects.values('username','password','dp_id','dp__title')
# for row in q:
# print(row['username'],row['dp__title'])
# 3.元祖
# q = models.UserInfo.objects.values_list('username','password','dp_id','dp__title')
# for row in q:
# print(row[0],row[3])
# 反向跨表查询
# 1.对象
# v = models.DePart.objects.all()
# for row in v:
# print(row.id,row.title,row.userinfo_set.all())
# 2.字典
# v = models.DePart.objects.values('id','title','userinfo__username','userinfo__password')
# for row in v:
# print(row)
# 3.元祖
# v = models.DePart.objects.values('id','title','userinfo__username','userinfo__password')
# for row in v:
# print(row)
# 自己写第三张表
def U2G(models.Model):
ui = models.ForeignKey('UserInfo')
ug = models.ForeignKey('UserGroup')
# 添加数据
models.U2G.objects.create(ui=1,ug=1)
models.U2G.objects.create(ui=1,ug=2)
models.U2G.objects.create(ui=2,ug=1)
models.U2G.objects.create(ui=2,ug=2)
# 查询
q = models.U2G.objects.all()
for row in q:
print(row.ui.username)
print(row.ug.caption)
# django 自动生成
m = models.ManyToManyField('UserInfo')
增加：
obj = models.UserGroup.objects.filter(id=2).first()
obj.m.add(1)
obj.m.add(1,2,3)
obj.m.add(*[1,2]) #一次多加一个
删除：
obj = models.UserGroup.objects.filter(id=2).first()
obj.m.remove(1)
obj.m.remove(2,3,4)
obj.m.remove(*[2,3,4])
清空：
obj.m.clear() # 没有参数
更新：设置为什么， 最后就只有什么
obj.m.set([3,])
查询：
q = obj.m.all()
print(q)
q = obj.m.filter()