I don't really know, because AbstractConcreteBase works pretty poorly and it's
better to use other patterns.
Try this workaround, which I have no idea if it helps in this case:
class A(...):
# ...
@classmethod
def __declare_last__(cls):
cls.__mapper__.with_polymorphic = ("*", cls.__mapper__.local_table)
otherwise provide a more complete example and I'll try to diagnose why it
doesnt work for this case.
On Wed, Mar 25, 2020, at 12:30 PM, Benjamin Beguin wrote:
> Hi there,
>
> I'm facing an issue with the use of AbstractConcreteBase class and a
> @declarred_attr returning a query_expression()
>
>
> class A(AbstractConcreteBase, Base):
> @declared_attr
> def foo(cls):
> return query_expression()
>
>
> class B(A):
> ...
>
>
> class C(A):
> ...
>
>
> objects = db.session.query(A).options(with_expression(A.foo,
> my_expression)).all()
>
>
>
> B and C objects returned have the property foo but it is None
> The generated SQL query returns a value for the expression but the mapping
> seems to be not effective
>
> Am I doing something wrong ?
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
>
> To post example code, please provide an MCVE: Minimal, Complete, and
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--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
Example. See http://stackoverflow.com/help/mcve for a full description.
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