That is useful for mapping single or combined columns to an attribute. Here, I want to map entire objects.
On Nov 10, 10:20 pm, Eric Ongerth <[email protected]> wrote: > Good point, Sergey. > > Here is the relevant documentation regarding mapping attributes to > selects:http://www.sqlalchemy.org/docs/orm/mapper_config.html?highlight=arbit... > > On Nov 10, 4:46 pm, "Sergey V." <[email protected]> wrote: > > > > The twist is that I've spread out my tables and ORM classes across > > > several files. I've tried to keep it so that I don't have circular > > > dependencies. That means I've defined Merchant first, and then Deal > > > later, in separate files > > > To avoid problems with imports and dependencies you can pass strings > > to the relationship function instead of the actual classes: > > > mapper(Deal, deals, properties=dict( > > merchant=relationship('Merchant', backref='deals'), > > )) > > > This greatly simplifies everything if you split your classes into > > separate files. > > > Regarding 'available_deals', 'deleted_deals' etc. - the approach with > > properties is sub-optimal. Consider a merchant having thousands of > > deals, only a few of which are available - the method would have to > > fetch all those deals only to discard most of them. Also, that won't > > work with eager loading. The optimal way would be to make SA to > > generate a query like "SELECT ... FROM Deals WHERE ... AND deleted=1" > > which would return only the records we're interested in. I'm sure it's > > possible but I'll leave it to you to find it in SA docs :) When you > > find it please post it here :) -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to [email protected]. 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.
