wild guess: do u need relations_table.id? rename/remove it
On Tuesday 11 September 2007 12:34:47 KyleJ wrote:
> I get the same result with this in 0.3.10 and 0.4beta5....
>
> Basic idea: I have two tables which hold various data and a third
> table which let's different rows in each table be related to
> another (many-to-many relationship).
>
> Table/ORM code:
> base_table = Table('base_type', metadata,
> Column('id', types.Integer, primary_key=True,
> autoincrement=True), Column('name', types.String(255),
> nullable=False, default=''), Column('pickledData',
> types.PickleType)
> )
>
> people_table = Table('people', sac.metadata,
> Column('id', types.Integer, primary_key=True,
> autoincrement=True), Column('name', types.String(255),
> nullable=False, default=''), Column('email', types.String(255),
> nullable=False, default=''), Column('pickledData',
> types.PickleType)
> )
>
> relations_table = Table('relations', sac.metadata,
> Column('id', types.Integer, primary_key=True,
> autoincrement=True), Column('toObj', types.Integer, default=0),
> Column('fromObj', types.Integer, default=0),
> Column('toType', types.Integer, default=0),
> Column('fromType', types.Integer, default=0)
> )
>
> class BaseType(object): # type 0
> pass
> class Person(object): # type 1
> pass
>
> mapper(Person, people_table) # <-- not complete yet, just trying to
> get basic many-to-many working below
> mapper(BaseType, base_table, properties={
> 'people': relation(Person, secondary=relations_table,
> viewonly=True,
> primaryjoin=and_(people_table.c.id ==
> relations_table.c.fromObj, relations_table.c.fromType == 1),
> secondaryjoin=and_(base_table.c.id ==
> relations_table.c.toObj, relations_table.c.toType == 0),
> foreign_keys=[relations_table.c.fromObj]),
> 'base': relation(BaseType, secondary=relations_table,
> viewonly=True,
> primaryjoin=and_(base_table.c.id ==
> relations_table.c.fromObj, relations_table.c.fromType == 0),
> secondaryjoin=and_(base_table.c.id ==
> relations_table.c.toObj, relations_table.c.toType == 0),
> foreign_keys=[relations_table.c.fromObj])
> })
>
>
> So, I do a query on BaseType, and take the first item and then
> iterate through the people property:
> base_q = Session.query(BaseType)
> item = base_q.get_by(id=0)
> if item:
> for person in item.people:
> print person.name
>
> Which raises an exception:
> sqlalchemy.exceptions.InvalidRequestError: Column 'people.id' is
> not available, due to conflicting property
> 'id':<sqlalchemy.orm.properties.ColumnProperty object at
> 0x2aaaaaac3910>
>
>
> My guess is it's something to do with foreign_keys (from my
> searching here, it would appear foreign_keys isn't a way to
> "pretend" that foreign keys exist in the schema).
>
> Any help would be greatly appreciated. :)
>
>
>
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