Hi guys,
Been trying to work this out. I have an existing database that I would like
to use sqlalchemy on. The code below is working in the sense that I can
query individual tables and joins do not fail ( where a FK reference exists
in the db ) but I can't seem to get references working.
engine = create_engine("postgresql:///local")
metadata = MetaData()
metadata.reflect(engine, only=['a', 'b'])
Base = automap_base(metadata=metadata)
class A(Base):
__tablename__ = 'table_a'
class B(Base):
__tablename__ = 'table_b'
a_ref = relationship('A', backref='b_ref')
Base.prepare(engine)
Note the 'only' in the metadata is because there are some tables in the
database causing trouble with the full reflect and I don't need them for
now so ignoring them. No errors when I load just these 2.
There is a real FK relationship in the database from B to A ( and I can see
it gets reflected properly in b.__table__.foreign_keys ) but for some
reason 'a_ref' is not defined on the instance returned by queries ( so
instance.a_ref would throw an AttributeError ). I know it must be something
small I'm missing but I can't seem to get it.
Any help would be appreciated.
Cheers,
Dermot
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