Hi Michael, this is amazing, thanks!!!
On Thursday, September 10, 2015 at 3:35:39 PM UTC+2, Michael Bayer wrote: > > > > On 9/10/15 8:48 AM, Pavel S wrote: > > Let's say, I have declarative classes A, B, C, D. > > A is the parent > B has FK&relationship to A > C has FK&relationship to B, > D has FK&relationship to C etc... > > I'd like to implement *generic method* walk(obj) which will recursively > yield dependent/related objects of obj (which is instance of A). > > I know that there is introspection interface inspect(), however I'm don't > really understand how to use it properly in my use case. > > Shall I do inspect(obj) or rather inspect(obj.__class__) and then somehow > apply inspection to obj? > > Are there an examples and best practices? > > right now you can kind of get this effect using cascade_iterator: > http://docs.sqlalchemy.org/en/rel_1_0/orm/mapping_api.html?highlight=cascade_iterator#sqlalchemy.orm.mapper.Mapper.cascade_iterator > > the limitation is that right now its based on relationship cascade > settings, as that's what it was intended for, so you'd probably want to use > "save-update": > > insp = inspect(my_object) > for obj in insp.mapper.cascade_iterator("save-update", insp): > # ... > > to implement your own system, the graph of objects is strictly based on > relationship. so walk() is pretty simple: > > def walk(obj): > yield obj > insp = inspect(obj) > for relationship in insp.mapper.relationships: > related = getattr(obj, relationship.key) > if relationship.uselist: > for collection_member in related: > for walk_related in walk(collection_member): > yield walk_related > elif related is not None: > for walk_related in walk(related): > yield walk_related > > > > > > > -- > You received this message because you are subscribed to the Google Groups > "sqlalchemy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sqlalchemy+...@googlegroups.com <javascript:>. > To post to this group, send email to sqlal...@googlegroups.com > <javascript:>. > Visit this group at http://groups.google.com/group/sqlalchemy. > For more options, visit https://groups.google.com/d/optout. > > > -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
