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djangomodels

How to set already existing field as a foreign key to another table?

A have two model tables which contains data. 

class A(models.Model):
    id = models.PositiveIntegerField(primary_key=True)
    #some other fields
    other_id = models.IntegerField(default=0, null=True)

And the second class

class B(models.Model):
    id = models.PositiveIntegerField(primary_key=True)
    #some other fields

Now I want field A.other_id to become a ForeignKey related to field B.id. I cannot use SQL. I know it is supposed to be something like:

b = models.ForeignKey(B, db_column="other_id")

but it seems to not work.

Solution

  • Did you try to_field option?

    You can do:

     b = models.ForeignKey(B, to_field="other_id")

    However, the catch is that field other_id must satisfy unique=True.