标签:set 库表时 author many Author django objects id
创建对象时,多对多字段不能直接通过下面的方式处理:
from .models import Blog, Author, User
author = Author.objects.get(id=1)
users = User.objects.filter(id__in=(2, 3, 4))
# 这样直接写过不了,会报错: Direct assignment to the forward side of a many-to-many set is prohibited
Blog.objects.create(
author=author,
likes=users
)
会报错:TypeError: Direct assignment to the forward side of a many-to-many set is prohibited
在创建表时就添加多对多数据的话,可通过下面的方式来处理:
from .models import Blog, Author, User
author = Author.objects.get(id=1)
users = User.objects.filter(id__in=(2, 3, 4))
# 这样直接写过不了,会报错: Direct assignment to the forward side of a many-to-many set is prohibited
blog = Blog.objects.create(
author=author
)
# create的时候不写many to many 字段,写完后单独设置这些字段就可以了
blog.likes.set(users)
如果报错:ValueError: “needs to have a value for field ”id“ before this many-to-many relationship can be used”
from .models import Blog, Author, User
author = Author.objects.get(id=1)
users = User.objects.filter(id__in=(2, 3, 4))
# 这样直接写过不了,会报错: Direct assignment to the forward side of a many-to-many set is prohibited
blog = Blog(
author=author
)
# create的时候不写many to many 字段,写完后单独设置这些字段就可以了
blog.likes.set(users)
这是由于没有用create来创建,直接用Bolg来创建了,正确的是下面
from .models import Blog, Author, User
author = Author.objects.get(id=1)
users = User.objects.filter(id__in=(2, 3, 4))
# 这样直接写过不了,会报错: Direct assignment to the forward side of a many-to-many set is prohibited
blog = Blog.objects.create(
author=author
)
# create的时候不写many to many 字段,写完后单独设置这些字段就可以了
blog.likes.set(users)
标签:set,库表时,author,many,Author,django,objects,id 来源: https://blog.csdn.net/Jason_WangYing/article/details/120657066
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