Class B

test/orm/test_eager_relations.py:197–201

        A.anything = column_property(A.id + 1000)

        class B(A):
            __tablename__ = "b"
            account_id = Column(Integer, ForeignKey("a.id"), primary_key=True)
            x_id = Column(Integer, ForeignKey("x.id"), nullable=False)
            __mapper_args__ = {"polymorphic_identity": "named"}

        class X(decl_base):
            __tablename__ = "x"