Django 1.7中的外键完整性错误

Question

I have a project where a user can review a service. Whenever I try to write a review with the same user twice, I get an Integrity error:

duplicate key value violates unique constraint "reviews_review_user_id_key" DETAIL: Key (user_id)=(7) already exists.

I'm not too sure why I am getting this error. Is it because there should be a many-to-many relation between users and reviews?

The review model looks like this:

class Review(models.Model):
    user = models.ForeignKey(User)
    service = models.ForeignKey('services.Service')
    rating_value = models.IntegerField(default = 0)
    review_text = models.CharField(max_length = 500, default= "null")
    pub_date = models.DateTimeField(default=timezone.now,blank=True)
    def __str__(self):              # __unicode__ on Python 2
        return self.service_name

Answer 1

It appears that you have removed the unique constraint in the models.py, but the unique constraint still exists on the database table. This has happened to me before and I was able to remove the constraint from the table through ./manage.py dbshell and everything worked as expected.

Not sure which db you're using, but for postgres it would be: ALTER TABLE your_table DROP CONSTRAINT reviews_review_user_id_key;

Give that a shot, hope it helps.