CODEWITHSUNDEEP
djangodjango-modelsmany-to-many
Tikitu
Tikitu

Reputation: 699

Django: Many-to-many through a table with (only) compound key

I have a legacy database with a table storing a many-to-many relationship, but without a single primary key column. Is there any way to convince Django to use it anyway?

Schematically:

Product 1<---->* Labeling *<---->1 Label

The Labeling table uses (product_id,label_id) as a compound primary key, and I don't see any way to inform Django about this. (Just using through gives me Unknown column 'labeling.id' in 'field list'.)

Do I need to fall back to custom SQL? Or am I missing something?

Upvotes: 6

Views: 3563

Answers (2)

Tikitu
Tikitu

Reputation: 699

If you add a unique_together to the model for the many-to-many table, Django will use those columns instead of expecting a primary key called id.

Upvotes: 1

Ashok
Ashok

Reputation: 10603

hope this helps you,

http://docs.djangoproject.com/en/dev/ref/models/options/#unique-together

http://docs.djangoproject.com/en/dev/ref/models/fields/#django.db.models.Field.db_index

Upvotes: 2

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