relationship() expects a class or a mapper instance, not a string. I
got this error:
ArgumentError: relationship 'available_deals' expects a class or a
mapper argument (received: <type 'str'>)
On Nov 10, 4:46 pm, "Sergey V." <sergey.volob...@gmail.com> 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 sqlalch...@googlegroups.com.
To unsubscribe from this group, send email to
sqlalchemy+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/sqlalchemy?hl=en.
