On Jun 10, 10:34 am, Malthe Borch <[EMAIL PROTECTED]> wrote:
> I have an issue with SQLAlchemy planning to execute insertion tasks in
> the wrong order.
>
> Basically, I have a utility table "Relations" which is used to maintain
> ordered list relations:
>
> table = rdb.Table(
> 'relation',
> metadata,
> rdb.Column('id', rdb.Integer, primary_key=True, autoincrement=True),
> rdb.Column('left', rdb.String(length=32),
> rdb.ForeignKey("soup.uuid"), index=True),
> rdb.Column('right', rdb.String(length=32),
> rdb.ForeignKey("soup.uuid")),
> rdb.Column('order', rdb.Integer, nullable=False))
>
> Now, I append a new, transient object to such an ordered list. That
> means that SQLAlchemy would make two inserts. The problem is that the
> tasks are ordered such that the *relation* is inserted before the object
> that is the target of the relation!
>
> This obviously raises an IntegrityError, since the foreign key
> constraint is not satisfied.
>
> My question is then: How do I tell SQLAlchemy to order them correctly?
>
> \malthe
A self-referential relationship, when configured as many-to-one,
requires the "remote_side" argument to indicate this, as described in
http://www.sqlalchemy.org/docs/04/mappers.html#advdatamapping_relation_selfreferential
. Otherwise it defaults to "one-to-many".
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