Constrain unique_together could have conflict with the unique_field in dajngo Class

Question

I would like to know if there is any conflict using the constraint unique_together as well as the parameter unique=true in one of the fields that belong to the array of the unique_together.

I can´t remove the parameter unique=true of my field because it´s used as a the foreign key in another model.

class User(AbstractUser):
  # User information
  fiscal_number = models.CharField(max_length=30,unique=True)
  phone = models.CharField(max_length=15, null=True)
  email = models.EmailField(max_length=254, verbose_name='email address')

  class Meta:
    unique_together = ['fiscal_number', 'email']

As you can see the goal is to make the combination of the fields fiscal_number and email unique.

Answer 1

Basically, I would like to know if there is any conflict using the constrain unique_together as well as the parameter unique=true in one of the fields that belong to the array of the unique_together.

It makes no sense. Indeed, by setting unique=True it means that there can't be two users with the same fiscal_number, unless if these two users are the same user.

The unique_together = ['fiscal_year', 'email'] means that the combination of a fiscal_year and an email has to be unique. That means that there can't be two users where both the fiscal_year and the email are the same (unless these two users are the same user). But since we already made fiscal_year as a field unique, we already know that this can not happen.

You can mark the email field as unique=True as well. This is not equivalent to unique_together = ['fiscal_number', 'email']. With unique_together, the combination of the two columns should be unique, whereas setting unique=True on multiple fields, means that all Users have a different fiscal_year, and a different email, etc.