what conditions would cause the "uselist" to be incorrect?
On Wed, Feb 5, 2020, at 4:22 PM, Jonathan Vanasco wrote:
> Does anyone know if there is an easy way to extend the relationships system
> so that I can specify the uselist I expect for back_populates relationships?
>
> One of my projects has a complex model with a mix of one-to-one and
> one-to-many relationships that declare `uselist`. I'd like to ensure I
> declare the correct `uselist` on each side of the relationship, and ensure an
> Exception is raised at runtime if one side is declared incorrectly.
>
> as a use-case example, I'd like to do something like:
>
>
>
> class Foo(Base):
> id = Column(Integer, primary_key=True)
> bars = relationship("Bar",
> primaryjoin="Foo.id==Bar.foo_id",
> uselist=True,
> back_populates="foo",
> back_populates_uselist=False, # ensure the `uselist` on the `back_populates`
> relationship is False
> )
>
>
> class Bar(Base):
> id = Column(Integer, primary_key=True)
> foo_id = Column(Integer)
> foo = relationship("Foo",
> primaryjoin="Bar.foo_id==Foo.id",
> uselist=False,
> back_populates="bars",
> back_populates_uselist=True, # ensure the `uselist` on the `back_populates`
> relationship is True
> )
>
>
>
>
>
>
> --
> SQLAlchemy -
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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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