I'm on the bleeding edge (could be why I'm having the
problem) cayenne 1.2M3.
Filip
On 4/25/05, Andrus Adamchik <andru..bjectstyle.org> wrote:
> You shouldn't have to do anything special. Cayenne (including the Modeler)
> works fine with simple parent-child hierarchies. For "children" I expect
> the generated query to look even simpler:
>
> SELECT t0.description, t0.id, t0.parent_id
> FROM dbo.IMV_locations t0, dbo.IMV_locations t1
> WHERE t0.parent_id = ? [bind: 1]
>
> So ... What version of Cayenne do you have? There was a bug long time ago
> that messed it up, but I am fairly sure it is fixed in 1.1 final and 1.1.1
> releases.
>
> Andrus
>
>
> > Hi Andrus,
> >
> > Yes that makes perfect sense. I didn't catch that error, I just
> > assumed the modeler would generate the right xml when
> > I selected the proper source and target.
> >
> > However, even when I corrected the xml manually to your
> > suggestion, I still have the following statement generated
> > by cayenne:
> >
> > SELECT t0.description, t0.id, t0.parent_id
> > FROM dbo.IMV_locations t0, dbo.IMV_locations t1
> > WHERE t0.parent_id = t1.id AND (t1.parent_id = ?) [bind: 1]
> >
> > I need it to read:
> >
> > SELECT t0.description, t0.id, t0.parent_id
> > FROM dbo.IMV_locations t0, dbo.IMV_locations t1
> > WHERE t0.parent_id = t1.id AND (t1.id = ?) [bind: 1]
> >
> > In another spot in my code I have a hierarchy set up but
> > it is a many to many (map, not tree) and cayenne seems
> > to deal with that beautifully. To achieve this I have an intermediate
> > table that maps locations to one another. Will I have to add
> > this extra table with a one-To-one constraint to ensure a tree
> > structure and not a map?
> >
> > Thanks to all who have answered.
> > Your help is greatly appreciated.
> > Filip
> >
> >
> >
> > On 4/24/05, Andrus Adamchik <andru..bjectstyle.org> wrote:
> >> Hi Filip,
> >>
> >> > <obj-relationship name="children" source="Location"
> >> target="Location" deleteRule="Cascade"
> >> > db-relationship-path="rel_children.rel_children"/>
> >> >
> >> > <obj-relationship name="parent" source="Location" target="Location"
> >> db-relationship-path="rel_parent.rel_parent"/>
> >>
> >> The way relationships above are mapped you'll be getting GRANDchildren
> >> and GRANDparents. Is this really what you want? The query you quote
> >> seems correct (for grandchildren). What I mean is that
> >>
> >>
> >> > SELECT t0.description, t0.id, t0.parent_id
> >> > FROM dbo.IMV_locations t0, dbo.IMV_locations t1
> >> > WHERE t0.parent_id = t1.id AND (t1.parent_id = ?) [bind: 1]
> >>
> >> is a short form for
> >>
> >> SELECT t0.description, t0.id, t0.parent_id
> >> FROM dbo.IMV_locations t0, dbo.IMV_locations t1, dbo.IMV_locations t2
> >> WHERE t0.parent_id = t1.id AND t1.parent_id = t2.id AND t2.id = ?
> >> [bind: 1]
> >>
> >> (see an extra join)... If you need direct children, then you need to
> >> remove the last component in the obj-relationship path. The resulting
> >> mapping should look like this:
> >>
> >>
> >> <obj-relationship name="children" source="Location" target="Location"
> >> deleteRule="Cascade"
> >> db-relationship-path="rel_children"/>
> >>
> >> <obj-relationship name="parent" source="Location" target="Location"
> >> db-relationship-path="rel_parent"/>
> >>
> >> I hope I understood your requirements correctly...
> >>
> >> Andrus
> >>
> >>
> >
> >
> > --
> > Cell : 403.461.7895
> > Work: 403.770.1534
> > MSN: fbala..otmail.com
>
>
-- Cell : 403.461.7895 Work: 403.770.1534 MSN: fbala..otmail.com
This archive was generated by hypermail 2.0.0 : Mon Apr 25 2005 - 16:47:47 EDT