更新时间:2022-12-05 20:53:57
可以通过在 OneToOneField
上设置 primary_key=True
指向 用户
模型,正如你自己想出来的那样.
The problem can be avoided by setting primary_key=True
on the OneToOneField
pointing at the User
model, as you have figured out yourself.
这行得通的原因似乎很简单.
The reason that this works seems to be rather simple.
当您尝试创建模型实例并在保存之前手动设置 pk
时,Django 将尝试使用该 pk
在数据库中查找记录并更新它而不是盲目地尝试创建一个新的.如果不存在,它会按预期创建新记录.
When you try to create a model instance and set the pk
manually before saving it, Django will try to find a record in the database with that pk
and update it rather than blindly attempting to create a new one. If none exists, it creates the new record as expected.
当您将 OneToOneField
设置为主键并且 Django 管理员将该字段设置为相关 User
模型的 ID 时,这意味着 pk
已设置,Django 将首先尝试查找现有记录.
When you set the OneToOneField
as the primary key and Django Admin sets that field to the related User
model's ID, that means the pk
is already set and Django will attempt to find an existing record first.
这是将 OneToOneField
设置为主键时发生的情况:
This is what happens with the OneToOneField
set as primary key:
User
实例,没有 id
.User
实例.
User
instance, with no id
.User
instance.
pk
(本例中为 id
)未设置,Django 尝试创建新记录.id
由数据库自动设置.post_save
挂钩为该 User
实例创建一个新的 Profile
实例.pk
(in this case id
) is not set, Django attempts to create a new record.id
is set automatically by the database.post_save
hook creates a new Profile
instance for that User
instance.Profile
实例,并将其 user
设置为用户的 id
.Profile
实例.
Profile
instance, with its user
set to the user's id
.Profile
instance.
pk
(在本例中为 user
)已设置,Django 尝试使用该 pk
获取现有记录.李>pk
(in this case user
) is already set, Django attempts to fetch an existing record with that pk
.如果你没有显式设置主键,Django 会添加一个使用数据库的 auto_increment
功能的字段:数据库将 pk
设置为下一个最大值那不存在.这意味着该字段实际上将留空,除非您手动设置它,因此 Django 将始终尝试插入新记录,从而导致与 OneToOneField
上的唯一性约束冲突.
If you don't set the primary key explicitly, Django instead adds a field that uses the database's auto_increment
functionality: the database sets the pk
to the next largest value that doesn't exist. This means the field will actually be left blank unless you set it manually and Django will therefore always attempt to insert a new record, resulting in a conflict with the uniqueness-constraint on the OneToOneField
.
这是导致原始问题的原因:
This is what causes the original problem:
User
实例,没有 id
.User
实例,post_save
钩子像以前一样创建一个新的 Profile
实例.Profile
实例,没有 id
(自动添加的 pk
字段).Profile
实例.
User
instance, with no id
.User
instance, the post_save
hook creating a new Profile
instance as before.Profile
instance, with no id
(the automatically added pk
field).Profile
instance.
pk
(本例中为 id
)未设置,Django 尝试创建新记录.user
字段中违反了表的唯一性约束.pk
(in this case id
) is not set, Django attempts to create a new record.user
field.