On Apr 8, 2011, at 12:12 PM, Hector Blanco wrote:
> Hello everyone:
>
> I have a tree-like structure (groups/nodes, basically) with Stores and
> StoreGroups. An store can belong only to one storeGroup, but an
> StoreGroup can contain stores or other storeGroups:
>
> class StoreGroup(BaseClass.BaseClass, Database.Base):
> """Represents a storeGroup"""
> __tablename__ = "store_groups"
> _id = Column("id", Integer, primary_key=True)
> _name = Column("name", String(50))
>
> _storeGroups = relationship("StoreGroup",
> secondary=store_group_groups, order_by=lambda:StoreGroup.name,
> primaryjoin=lambda: StoreGroup.id ==
> store_group_groups.c.store_groupA_id,
> secondaryjoin=lambda: StoreGroup.id ==
> store_group_groups.c.store_groupB_id,
> backref="parentGroup",
> collection_class=set)
> #_stores > Backref from "Store" class
>
> class Store(BaseClass.BaseClass, Database.Base):
> """Represents a store"""
> __tablename__ = "stores"
> _id = Column("id", Integer, primary_key=True)
> _name = Column("name", String(50))
> _number = Column("number", Integer)
> _timeZone = Column("time_zone", String(20))
>
> _storeGroupId = Column("store_group_id", Integer,
> ForeignKey("store_groups.id"))
> _storeGroup = relationship("StoreGroup", uselist=False,
> backref=backref("_stores",
> order_by=lambda:Store.name,
> collection_class=set)
> )
>
> So I would like to have a way to, given an "StoreGroup" id, to
> recursively iterate through the hierarchy (StoreGroup.storeGroups) and
> grab all the "Stores" found on said hierarchy.
>
> I have seen the example:
> http://www.sqlalchemy.org/trac/browser/examples/adjacency_list/adjacency_list.py
>
> but that needs the depth to look in in advance.
>
> I also saw:
> http://groups.google.com/group/sqlalchemy/msg/80ea8e712380bff4
>
> where apparently there's no "sqlalchemistic" way of doing it (it needs
> sql tools and raw queries). I was hoping that maaaaybe the information
> I have is outdated, and it's doable now (using SqlAlchemy 0.6.6)
that link doesn't appear to be relevant to what you are asking here. To
iterate as you asked, that would be:
group = session.query(StoreGroup).filter(StoreGroup._id==id).one()
stack = [group]
while stack:
g = stack.pop()
for store in g._stores:
do_something_with(store)
stack.extend(g._storeGroups)
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