Compound/Composite primary/unique key with Django

Question

How can you create models (and thus tables) with a compound (composite) primary/unique key using Django?

Solution 1

Django does not support compound primary keys. You can create a single compound unique key with Meta.unique_together.

Solution 2

if you want only unique mixed fields together use belowcode:

class MyTable(models.Model):
    class Meta:
        unique_together = (('key1', 'key2'),)

    key1 = models.IntegerField()
    key2 = models.IntegerField()

But if you want unique together and one of column be primary, set primary argument for model column, similar below code:

class MyTable(models.Model):
    class Meta:
        unique_together = (('key1', 'key2'),)

    key1 = models.IntegerField(primary_key=True)
    key2 = models.IntegerField()

Solution 3

A composite key consists of more than one attribute to uniquely identify an entity occurrence. This differs from a compound key in that one or more of the attributes, which make up the key, are not simple keys in their own right.

For example, you have a database holding your CD collection. One of the entities is called tracks, which holds details of the tracks on a CD. This has a composite key of CD name, track number.