Django: Does unique_together imply db_index=True in the same way that ForeignKey does?

For anyone coming here wondering if they need an index_together in addition to unique_together to get the index's performance benefit, the answer for Postgres is no, they are functionally the same.

If unique_together does add an index, it will be a multiple column index.

If you want one of the columns to be indexed individually, I believe you need to specify db_index=True in the field definition.

In Django 1.5 and higher, you can use the {Model}.Meta.index_together class attribute. If you had two fields named foo and bar, you would add:

class Meta(object):
    index_together = unique_together = [
        ['foo', 'bar']
    ]

If you have only one set of unique fields, you can use a one-dimensional iterable for unique_together. However, the documentation does not indicate that the same applies to index_together.

This would also be okay:

class Meta(object):
    unique_together = 'foo', 'bar'
    index_together = [
        ['foo', 'bar']
    ]

This, however, is NOT supported by the documentation:

class Meta(object):
    unique_together = 'foo', 'bar'
    index_together = 'foo', 'bar'