That was exactly what I was looking for. Thanks a lot :-) Simon
On 21 Aug., 19:57, Michael Bayer <mike...@zzzcomputing.com> wrote: > On Aug 21, 2010, at 12:05 PM, simon wrote: > > > Hi all, > > > For a given declaratively mapped class in SA 0.6, how do I > > programmatically find out all other mapped classes forming a many-to- > > one or many-to-many relationship with it? I know I can ask a table > > object for all its foreign keys, but the information whether it forms > > a many-to-one or a many-to-many relationship is not really contained > > in the schema. > > Assuming that relationship() has been configured, you'd retrieve the Mapper > for each class: > > from sqlalchemy.orm import class_mapper > > mapper = class_mapper(someclass) > > you can then iterate through its properties looking for what you need, but > note the API of MapperProperty/RelationshipProperty is less stable than that > of primary ORM constructs: > > from sqlalchemy.orm.properties import RelationshipProperty > from sqlalchemy.orm.interfaces import MANYTOMANY, MANYTOONE > > for prop in mapper.iterate_properties: > if isinstance(prop, RelationshipProperty): > prop.direction in (MANYTOMANY, MANYTOONE) ... > > if OTOH your asking for relationship() to be generated automatically, there's > no completely reliable way to tell if an FK is many to one or many to many, > unless you want to make a guess based on the other columns and constrants on > the referencing table. > > > > > Thanks, Simon > > > -- > > You received this message because you are subscribed to the Google Groups > > "sqlalchemy" group. > > To post to this group, send email to sqlalch...@googlegroups.com. > > To unsubscribe from this group, send email to > > sqlalchemy+unsubscr...@googlegroups.com. > > For more options, visit this group > > athttp://groups.google.com/group/sqlalchemy?hl=en. -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalch...@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
