On Wed, May 30, 2018 at 12:39 PM, Derek Lambert
<dlamb...@dereklambert.com> wrote:
> Outside of checking the discriminator value is it possible to filter a query
> by a class in an inheritance mapping?
>
> class Employee(Base):
> __tablename__ = 'employee'
> id = Column(Integer, primary_key=True)
> name = Column(String(50))
> type = Column(String(20))
>
> __mapper_args__ = {
> 'polymorphic_on':type,
> 'polymorphic_identity':'employee'
> }
>
> class Manager(Employee):
> manager_data = Column(String(50))
>
> __mapper_args__ = {
> 'polymorphic_identity':'manager'
> }
>
> class Engineer(Employee):
> engineer_info = Column(String(50))
>
> __mapper_args__ = {
> 'polymorphic_identity':'engineer'
> }
>
> and then query something like:
>
> engineers = session.query(Employee).filter(isclass(Engineer)).all()
I'm sure you know the easiest way is query for that class:
sess.query(Engineer).all()
short of that you can try changing the entitiy:
sess.query(Employee).with_entities(Engineer).all()
>
> --
> 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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--
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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