On Sep 6, 2012, at 6:55 PM, Kuba Dolecki wrote:
> Hello,
>
> I have been struggling for a few hours with the following issue. First, the
> models:
>
> stack_resources = db.Table('stack_resources',
> db.Column('stack_id', db.Integer, db.ForeignKey('stack.id')),
> db.Column('resource_id', db.Integer, db.ForeignKey('resource.id'))
> )
>
> class Stack(BaseObject, db.Model):
> id = some primary key
>
> resources = db.relation('Resource',
> secondary=stack_resources,
> secondaryjoin="and_(Resource.id==stack_resources.c.resource_id, \
> Resource.top_parent_resource==True)",
> backref=db.backref('stacks'))
>
> class Resource(BaseObject, db.Model):
> id = some primary key
>
> top_parent_resource = db.Column(db.Boolean)
>
> The issue lies with the query emitted. Here's the query for getting the
> Resources associated with a stack:
>
> SELECT ALL THE THINGS FROM RESOURCES
> FROM resource, stack_resources
> WHERE %s = stack_resources.stack_id AND resource.id =
> stack_resources.resource_id AND resource.top_parent_resource = %s
>
> Basically, what appears to be missing is "AND stack.id =
> stack_resources.stack_id". Anything I'm missing in the relationship
> configuration that would make that happen?
if that's the "lazyload" query, meaning you have a Stack object loaded into
memory and you're saying mystack.resources to access the "resources"
collection, the query is correct. You'll note the clause "%s =
stack_resources.stack_id"' the primary key of your Stack object (which you'd
see by saying "mystack.id") is passed as a bound parameter to the query and
replaces where you see the %s. You would also see the query in the parameter
set which follows the SELECT statement if you're using echo=True on your Engine.
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