AttributeError while querying: Neither 'InstrumentedAttribute' object nor 'Comparator' has an attribute

Question

The following code:

Base = declarative_base()
engine = create_engine(r\"sqlite:///\" + r\"d:\\foo.db\",
                       listeners=[ForeignKeysListener()])         


        

Answer 1

A related error that can be caused by configuring your SQLAlchemy relationships incorrectly:

AttributeError: Neither 'Column' object nor 'Comparator' object has an attribute 'corresponding_column'

In my case, I incorrectly defined a relationship like this:

namespace   = relationship(PgNamespace, id_namespace, backref="classes")

The id_namespace argument to relationship() should just not be there at all. SQLAlchemy is trying to interpret it as an argument of a different type, and failing with an inscrutable error.