Re: More than one primary key for a model

No, it doesn't use unique_together to do the joins, but
unique_together will enforce the uniqueness constraint of the compound
key, and allow you to do a lookup of an object based on the compound
key.

As Bruno explained, you'll have to use for surrogate primary keys the
auto-generated integer primary keys that Django creates if you don't
declare a primary key for the model, and let Django do its joins on
that. The only other option (i.e. if you're working with a database
that already exists and you can't change) would be to do all your
queries in raw SQL and write the joins yourself.

On Jun 28, 1:27 pm, thusjanthan <thusjant...@gmail.com> wrote:
> Yes you are correct I am looking to implement the compounded primary
> keys. Well the problem is I would like to have a many to many(m2m)
> with two models that share a compounded primary key. However when I do
> the m2m join it randomly pics one of the compounded keys and tries to
> join them? :| Does the unique_together parameter fix that problem? as
> in does it use the unique_together to do the joins?
>
> On Jun 28, 10:20 am, ringemup <ringe...@gmail.com> wrote:
>
> > By definition a database table can have only one primary key.  I
> > believe what you're looking to implement are compound primary keys.
> > Depending on the database backend you're using, the unique_together
> > Meta attribute may accomplish most of what you're looking to do.
>
> > On Jun 28, 12:49 pm, thusjanthan <thusjant...@gmail.com> wrote:
>
> > > Can anyone tell me why django refuses to follow the rules and lesson
> > > we learn in our database courses?
>
> > > I have a table that I do not have control over. Suppose its called the
> > > phone table and it contains the number and the username as the primary
> > > key. But for some reason when I have more than one primary key in
> > > django it complains. Especially when I run the test suite it just
> > > craps out saying more than one primary key detected for a model. Does
> > > django really expect all tables to only contain one primary key? How
> > > can I override this feature and have it take more than one primary key
> > > without using things suggested by django about the unique attr in the
> > > meta info of the model.
>
> > > Thanks.
> > > Nathan.
>
>

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