On Apr 4, 2011, at 1:49 PM, writeson wrote:
> Hi all,
>
> I've got a function that makes the following query:
>
> results = session.query(Order) \
> .filter_by(reference=reference) \
> .order_by(asc(Order.order_id)) \
> .options(eagerload("item"), \
> eagerload("state_ref"), \
> eagerload("item.book_ref"), \
> eagerload("item.cover_type_ref"), \
> eagerload("item.cover_material_ref"), \
> eagerload("item.cover_color_ref"), \
> eagerload("item.book_ref.product_ref")) \
> .add_column((Order.item.gross *
> Order.item.qty).label("total"))
> .all()
>
> where item and state_ref are FK references in Order and book_ref,
> cover_type_ref, cover_material_ref and cover_color_ref are FK
> reference in Item and product_ref is a FK refeference in Book.
>
> I want to add a new column to create a "total" for each row returned
> from Order, but I'm getting the following exception when the
>
> .add_column((Order.item.gross * Order.item.qty).label("total"))
>
> is executed:
>
> AttributeError: Neither 'InstrumentedAttribute' object nor
> 'Comparator' object has an attribute 'gross'
>
> How can I make add_column() aware of the to gross and qty I want to
> multiple together?
columns are always from the entity:
.add_column(Item.gross * Item.qty)
eagerload() is not used for joins that you can further filter or order from.
You use query.join() for that. See
http://www.sqlalchemy.org/docs/orm/tutorial.html#querying-with-joins as well as
the note in
http://www.sqlalchemy.org/docs/orm/loading.html#sqlalchemy.orm.joinedload
regarding this. A specific FAQ entry regarding this is at
http://www.sqlalchemy.org/trac/wiki/FAQ#ImusinglazyFalsetocreateaJOINOUTERJOINandSQLAlchemyisnotconstructingthequerywhenItrytoaddaWHEREORDERBYLIMITetc.whichreliesupontheOUTERJOIN
.
>
> Thanks in advance for your help!
> Doug
>
> --
> 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.
>
--
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.
