ah yes well thats is sort of intentional...the old _get_direction
code was looking at which table had the "primary key" column and that
was breaking when people related tables together via both primary
keys....so now its more accurately looking at the foreign key
relations to the various tables. Its intuitive that if your tables
dont have ForeignKeys on them, you have to tell the Mapper what the
"mapped" foreign keys are.
On Jun 14, 2006, at 4:51 PM, Chris Perkins wrote:
> On 6/14/06, Michael Bayer <[EMAIL PROTECTED]> wrote:
>> no thats possibly a little weird...you should send me what youre
>> doing so i can see what thats about. is this only with self-
>> referential mappers ?
>
> Well, maybe I'm doing something that's weird. Again, here's a minimal
> example - the weirdness comes from having an unenforced ForeignKey,
> because there is more than one table that it might refer to (a Car
> could belong to a Company, or to a Person)
>
> #### Begin code ####
>
> from sqlalchemy import *
>
> meta = BoundMetaData('sqlite://', echo=False)
>
> company_table = Table('company', meta,
> Column('id', Integer, primary_key=True),
> Column('name', String),
> )
>
> person_table = Table('person', meta,
> Column('id', Integer, primary_key=True),
> Column('name', String),
> )
>
> car_table = Table('car', meta,
> Column('id', Integer, primary_key=True),
> # owner_id is sort-of, but not really, an FK - it could refer
> # to a company or to a person:
> Column('owner_id', Integer, nullable=False),
> )
>
> meta.create_all()
>
> class Car(object):
> pass
> class Company(object):
> pass
> class Person(object):
> pass
>
> Car.mapper = mapper(Car, car_table)
> Company.mapper = mapper(Company, company_table)
> Person.mapper = mapper(Person, person_table)
>
> if True:
> # This doesn't work...
> Company.mapper.add_property(
> 'cars',
> relation(Car, primaryjoin=
> (car_table.c.id==company_table.c.id)))
> Person.mapper.add_property(
> 'cars',
> relation(Car, primaryjoin=
> (car_table.c.id==person_table.c.id)))
> else:
> # but this does.
> Company.mapper.add_property(
> 'cars',
> relation(Car, primaryjoin=
> (car_table.c.id==company_table.c.id),
> foreignkey=[car_table.c.id]))
> Person.mapper.add_property(
> 'cars',
> relation(Car, primaryjoin=(car_table.c.id==person_table.c.id),
> foreignkey=[car_table.c.id]))
>
> #### End code ####
>
> I have been doing something like this for a few days, and it worked
> until I synced with svn today.
>
> As you see in the example, I can work around it quite easily, so it's
> not slowing down my work.
>
> Chris Perkins
>
>
> _______________________________________________
> Sqlalchemy-users mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/sqlalchemy-users
_______________________________________________
Sqlalchemy-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/sqlalchemy-users
