actually, use passive_deletes=True, not 'all'. It will issue DELETEs only for collections that are already loaded, this doesn't break anything and prevents unnecessary SELECTs of unloaded collections. The True setting is needed so that the session can update the state of those collections during the flush process.
On Dec 5, 2008, at 12:29 PM, Michael Bayer wrote: > use the "passive_updates=True, passive_deletes='all'" flags. These > are described at > http://www.sqlalchemy.org/docs/05/sqlalchemy_orm.html#docstrings_sqlalchemy.orm_modfunc_relation > > . > > > On Dec 5, 2008, at 11:42 AM, James Brady wrote: > >> Hi all, >> I'm trying to get deletes and updates cascaded down from a parent >> object to the child objects (connected by ForeignKey). >> >> It all seems pretty simple in the docs, but I can't get it to work! >> I'm using MySQL with the InnoDB engine, and have played with all >> the variation of the onupdate, ondelete and cascade arguments I can >> think of. >> >> The problem is that immediately before the DELETE command is sent >> to MySQL, there are UPDATE commands nulling out the foreign key >> references of the child objects, so MySQL doesn't trigger it's ON >> DELETE CASCADE action, and for some reason cascade="all, delete- >> orphan" doesn't clean up the children with NULL FKs. >> >> Here's a simplified model: >> users_table = Table('tg_user', metadata, >> Column('user_id', Integer, primary_key=True), >> Column('created', DateTime, default=datetime.now), >> mysql_engine='InnoDB', >> ) >> >> hat_table = Table('hat', metadata, >> Column('id', Integer, primary_key=True), >> Column('name', Unicode(100)), >> Column('user_id', Integer, ForeignKey('tg_user.user_id'), >> onupdate='CASCADE', ondelete='CASCADE'), >> mysql_engine='InnoDB', >> ) >> >> class User(object): >> pass >> >> class Hat(object): >> pass >> >> mapper(User, users_table) >> >> mapper(Hat, hat_table, >> properties = { >> 'user': relation(User, backref="hats", cascade="all, >> delete, delete-orphan"), >> } >> ) >> >> And the log from SA when I do a User.delete: >> BEGIN >> UPDATE hat SET user_id=%s WHERE hat.id = %s >> [None, 1L] >> DELETE FROM tg_user WHERE tg_user.user_id = %s >> [1L] >> COMMIT >> >> Any help would be much appreciated! >> >> James >> >> >> > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---
