[sqlalchemy] Inherited abstract model with relationship causing "Cannot compile Column object until its 'name' is assigned."

[TomS.]

Hi,

I would like to create an abstract model which should be inherited. 
Unfortunately, I am not allowed to used Foreign Keys, this is the reason 
why I introduced work around via relationship. Here is the whole code:

class DepTest(db.Model):

    __tablename__ = u'deptest'
    __bind_key__ = u'section'

    department_pk_id = db.Column(db.Integer, primary_key=True)
    department_id = db.Column(db.Integer)
    department_name = db.Column(db.String(1000))


class PPLTest(db.Model):

    __abstract__ = True

    person_pk_id = db.Column(db.Integer, primary_key=True)
    person_name = db.Column(db.String(1000))
    person_surname = db.Column(db.String(1000))
    department_id = db.Column(db.Integer)

    @hybrid_property
    def person_name_surname(self):
        return self.person_name + u' ' + self.person_surname


class Level1(PPLTest):

    __tablename__ = u'ppl_level1'
    __bind_key__ = u'section'

    department = relationship(
        DepTest,
        primaryjoin=remote(DepTest.department_id) == foreign(
            PPLTest.department_id))


But I get "Cannot compile Column object until its 'name' is assigned."

So I defined department (in Level1) using @declared_attr:

    def department(clss):
        return relationship(DepTest,
                            primaryjoin=lambda: 
remote(DepTest.department_id) == foreign(
                                clss.department_id)
                            )

and now it works as expected. The question is - is it defined properly, 
or I should be aware of sth?

Thank you for any suggestions!

Cheers

--
You received this message because you are subscribed to the Google Groups 
"sqlalchemy" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to sqlalchemy+unsubscr...@googlegroups.com.
To post to this group, send email to sqlalchemy@googlegroups.com.
Visit this group at https://groups.google.com/group/sqlalchemy.
For more options, visit https://groups.google.com/d/optout.