Ummmm, not exactly sure what everyone means
by backwards in this context. But I did use the cayenne
modeler to create the relationships and the output I
posted previously was from the logger in the eclipse console,
so again generated by cayenne. I did nothing but write
a little test loop to go through each root location and
try to fetch children.
Each Location has the following attributes:
id (primary key)
parent_id (id of the parent, can be null)
description (name of location)
Source is a Location.
Target is a Location.
Now the child relationship states that if:
Source.id = Target.parent_id
Then the target is your child.
The parent relationship states that if:
Source.parent_id=Target.id
Then target is your parent.
I am not a proud man, please correct me
if I'm not understanding how the cayenne
modeler iterprets the mapping of these
things ;-D
Filip
On 4/22/05, Cris Daniluk <cris.danilu..mail.com> wrote:
> Actually, it looks backward to me too (though no morning coffee yet,
> so maybe you're right)... you know that if the relationships are
> backward and you use Cayenne to create the tree, then of course
> reading it will be backward too, right? Sounds like you were using
> Cayenne for both ends...
>
> And of course, getChildren should always be a toMany.
>
> On 4/22/05, Filip Balas <fbala..mail.com> wrote:
> > Well would you care to share this strange thinking
> > with the group? Considering that the 'parent' relationship
> > works as expected, it seems unlikely that my
> > relation is upside-down. If I were to invert the relation
> > (which I did try before posting) then getChildren returns
> > one obejct (and not a list as it should) which is it's
> > parent. 'getParent' then becomes the problem.
> >
> > Filip
> >
> >
> > On 4/22/05, Jürgen Saar <jsaa..eb.de> wrote:
> > > I've had the same problem with self referencing,
> > > on my first try.
> > >
> > > Your relation is upside-down
> > >
> > > It needs a little strange thinking to get it right.
> > >
> > > cayenne-use..bjectstyle.org schrieb am 22.04.05 00:35:02:
> > > >
> > > > I'm not sure if this has already been covered as
> > > > there doesn't seem to be a search facility for the
> > > > mailing list.
> > > >
> > > > My problem is that I have a simple hierarchy with
> > > > locations. A location can have child locations and
> > > > vice verca can have a parent:
> > > >
> > > > Schema:
> > > > --------------
> > > > id
> > > > parent_id
> > > > description
> > > >
> > > > Now I have modeled this relationship and the modeler
> > > > generated the following:
> > > >
> > > > <db-entity name="IMV_locations" schema="dbo" catalog="GPSForecast">
> > > > <db-attribute name="description" type="VARCHAR" length="75"/>
> > > > <db-attribute name="id" type="INTEGER" isPrimaryKey="true"
> > > > isMandatory="true" length="10"/>
> > > > <db-attribute name="parent_id" type="INTEGER" length="10"/>
> > > > </db-entity>
> > > >
> > > > <db-relationship name="rel_children" source="IMV_locations"
> > > > target="IMV_locations" toMany="true">
> > > > <db-attribute-pair source="id" target="parent_id"/>
> > > > </db-relationship>
> > > >
> > > > <db-relationship name="rel_parent" source="IMV_locations"
> > > > target="IMV_locations" toMany="false">
> > > > <db-attribute-pair source="parent_id" target="id"/>
> > > > </db-relationship>
> > > >
> > > > <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"/>
> > > >
> > > > Now when I run some test code to build a tree in tapestry, the
> > > > following statement gets genereated when I try to fetch children:
> > > >
> > > > 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]
> > > >
> > > > This however incorrect, it should 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]
> > > >
> > > > Has anyone else had this problem?
> > > > Filip
> > >
> > > __________________________________________________________
> > > Mit WEB.DE FreePhone mit hoechster Qualitaet ab 0 Ct./Min.
> > > weltweit telefonieren! http://freephone.web.de/?mc=021201
> > >
> > >
> >
> > --
> > 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 : Fri Apr 22 2005 - 11:27:43 EDT