Django独一无二（带外键） [英] Django Unique Together (with foreign keys)

问题描述

我有一种情况，我想使用 unique_together 的元选项执行某个规则，这里是中介模型：

I have a situation where I want to use the Meta options of unique_together to enforce a certain rule, here's the intermediary model:

class UserProfileExtension(models.Model):
    extension = models.ForeignKey(Extension, unique=False)
    userprofile = models.ForeignKey(UserProfile, unique=False)
    user = models.ForeignKey(User, unique=False)  

    class Meta:
        unique_together = (("userprofile", "extension"),
                           ("user", "extension"),
                           # How can I enforce UserProfile's Client 
                           # and Extension to be unique? This obviously
                           # doesn't work, but is this idea possible without
                           # creating another FK in my intermediary model 
                           ("userprofile__client", "extension"))

和这里的UserProfile：

and here's UserProfile:

class UserProfile(models.Model):
    user = models.ForeignKey(User, unique=True)
    client = models.ForeignKey(Client)

谢谢。

推荐答案

你不能。

unique_together 子句直接转换为 SQL 唯一索引。您只能在单个表的列上设置这些列，而不是几个表的组合。

The unique_together clause is directly translated to the SQL unique index. And you can only set those on columns of a single table, not a combination of several tables.

您可以自行添加验证，只需覆盖 validate_unique 方法，并添加此验证。

You can add validation for it yourself though, simply overwrite the validate_unique method and add this validation to it.

文档： http://docs.djangoproject.com/en/dev/ref/models/instances/#django .db.models.Model.validate_unique

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