attributes defined in mapper do not show up in python attribute dict

[Former user]

When defining a property in the mapper using relation, this does not show up when doing

though other properties/attributes
defined in both the tables and the classes do.

Is there a reason for this inconsistency?

Eg.
'patient_cells' in mapper(Patient, patient_table,
                properties={'patient_cells':relation(Cell, backref='patient')}) should be listed.

Thanks, Faheem Mitha
        [e-mail]

[Mike Bayer]

dict will be empty if nothing has been placed in it.

For a description of the technique SQLAlchemy uses to instrument attributes, see http://www.python.org/doc/2.4.2/ref/descriptors.html .

example:

from sqlalchemy import *
from sqlalchemy.orm import *

metadata = MetaData()

foo = Table('nodes', metadata,
    Column('id', Integer, primary_key=True),
    Column('data', String)
)

class Foo(object):
    pass

mapper(Foo, foo)

f = Foo()
f.data = "some data"
assert f.__dict__['data']('data') == "some data"