I'm not sure if something broke during an upgrade, or if I just had bad
tests and this was always an issue (I am assuming the latter!)
I need to duplicate a relationship on a sqlalchemy ORM declarative object.
I was hoping i could just do this (or at one point i could!)
class Foo(DeclaredTable):
bar_id = Column(Integer, ForeignKey("bar.id"), nullable=True)
bar = relationship("Bar", primaryjoin="Foo.bar_id ==Bar.id", uselist=
False)
bar_alt = bar
While I can address `fooInstance.bar_alt` with ease, I trigger an
AttributeError. The second item seems to become the 'active' attribute and
the first item is unaccessible.
AttributeError: Neither 'InstrumentedAttribute' object nor 'Comparator'
object associated with Foo.bar has an attribute '_supports_population'
There seems to be a workaround where I do this:
class Foo(DeclaredTable):
bar_id = Column(Integer, ForeignKey("bar.id"), nullable=True)
bar = relationship("Bar", primaryjoin="Foo.bar_id ==Bar.id", uselist=
False)
Foo.bar_alt = Foo.bar
However, if there is a better way I would appreciate knowing it. I would
prefer to not monkeypatch the class like this for readability.
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The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
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