On Fri, Mar 28, 2014 at 1:16 AM, <[email protected]> wrote:
> Hi,
>
> I'm trying to configure a table with autoload but can't quite get the syntax
> to set up a self-relationship. This is my abbreviated) schema:
>
> CREATE TABLE sdssphoto.photoobj
> (
> pk bigint NOT NULL DEFAULT nextval('photoobj_pk_seq'::regclass),
> parent_photoobj_pk bigint
> CONSTRAINT photoobj_pk PRIMARY KEY (pk),
> CONSTRAINT parent_fk FOREIGN KEY (parent_photoobj_pk)
> REFERENCES sdssphoto.photoobj (pk) MATCH SIMPLE
> ON UPDATE NO ACTION ON DELETE NO ACTION,
> )
>
> and my code:
>
> class PhotoObj(Base):
>
> __tablename__ = 'photoobj'
> __table_args__ = {'autoload':True, 'schema':'sdssphoto'}
>
> children = relationship('PhotoObj', backref=backref('parent',
> remote_side=[PhotoObj.pk]))
>
> The error I get is "NameError: name 'PhotoObj' is not defined". I've tried
> many iterations, but can't quite seem to get this right. Any suggestions
> would be appreciated!
>
In Python, you can't refer to a class while it is being defined. In
this instance, you are using the bare name PhotoObj in the remote_side
parameter to your backref.
I *think* (but haven't tested) that you should be able to specify the
remote_side parameter as a string:
children = relationship('PhotoObj', backref=backref('parent',
remote_side='[PhotoObj.pk]'))
The alternative is to define the "children" relationship after the
class has been defined:
class PhotoObj(Base):
__tablename__ = 'photoobj'
__table_args__ = {'autoload':True, 'schema':'sdssphoto'}
PhotoObj.children = relationship(PhotoObj, backref=backref('parent',
remote_side=[PhotoObj.pk]))
Hope that helps,
Simon
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