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)