you can define them for the purposes of querying and mapping just as separate ForeignKey objects (i.e ForeignKey(customer_id) on customer_id, ForeignKey(username) on username), and it will figure out all the appropriate join conditions connected by AND.
for the purposes of having the metadata more closely resemble reality as well as issuing the proper CREATE statements, theres a ticket: http://www.sqlalchemy.org/trac/ticket/76 On Jun 13, 2006, at 11:04 AM, Arnar Birgisson wrote: > Hi there.. > > Is is it possible to describe multi-column foreign keys with SA > metadata? > > I.e. > > create table customers ( > customer_id string, > primary key (customer_id) > ) > > create table users ( > customer_id string, > username string, > primary key (customer_id, username), > foreign key (customer_id) references customers (customer_id) > ) > > create table preferences ( > customer_id string, > username string, > preference_id string, > preference_value string, > primary key (customer_id, username, perference_id), > foreign key (customer_id, username) references users (customer_id, > username) > ) > > This model is a made-up simplification of what I need to do.. but > basically it's the last foreign key I can't figure out if I can > describe with SA metadata. > > The only solution I see is to put a relation property on the "user" > mapper that uses a custom join condition. However, this is standard > SQL so shouldn't SA be able to handle this automatically if there is a > ForeignKey specification on the table-object? > > Arnar > > > _______________________________________________ > Sqlalchemy-users mailing list > Sqlalchemy-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/sqlalchemy-users _______________________________________________ Sqlalchemy-users mailing list Sqlalchemy-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/sqlalchemy-users
