Question

I’m using a polymorphic association in SQLAlchemy as described in this example. It can also be found in the examples directory in the SQLAlchemy source code.

Given this setup, I want to query for all Addresses that are associated with Users. Not a user but any user.

In raw SQL, I could do that like this:

select addresses.* from addresses 
join address_associations 
on addresses.assoc_id = address_associations.assoc_id
where address_associations.type = 'user'

Is there a way to do this using the ORM Session?

Could I just run this raw SQL and then apply the Address class to each row in the results?

Answer 1

ad-hoc joins using the ORM are described at:

http://www.sqlalchemy.org/docs/orm/tutorial.html#querying-with-joins

for address in sess.query(Address).join(Address.association).filter_by(type='users'):
    print "Street", address.street, "Member", address.member