Bill,
I just ran a quick test. Everything seems to be working as expected in
Cayenne. I couldn't reproduce the behavior you are describing. So I wonder
if there is any mapping issues? Could you send me your data map XML file. I
will take a look.
Andrus
At 11:11 AM 1/15/2003 +1000, Fan, Bill (AP - Australia) wrote:
>Ooops, Andrus,
>
>The line of ctxt.deleteObject(obj) will remove all the records in the
>ProjectUsers table regardless what record the obj is linked to.
>
>
>Bill
>
>
>
>-----Original Message-----
>From: Andrus Adamchik [mailto:andru..bjectstyle.org]
>Sent: Wednesday, January 15, 2003 9:22 AM
>To: cayenne-use..bjectstyle.org
>Subject: Re: 1:n deletion problem
>
>Craig, Bill,
>
>I think there is a solution that does not involve the nightly build (Or am
>I missing something in this discussion?). Simply delete an object after
>unsetting relationship:
>
>for(int i=0; i<projectuserss.size(); i++) {
> Projectuser obj = (Projectusers)projectuserss.get(i);
> user.removeFromProjectusersArray(obj);
>
> // !!! This Line Is Added
> ctxt.deleteObject(obj);
>}
>ctxt.commitChanges(Level.WARN);
>
>
>Andrus
>
> > Easy. Simply removing the projectuser from the user will not trigger
> > deletion. The behaviour you are seeing is quite correct (you may be
> > used to WebOBjects/EOF, where such relationships can be set up (Owns
> > destination) such that removing does delete the destination object.
> > Cayenne doesn't have that (yet... don't know if it will, we'll have to
> > discuss that on the dev list).
> >
> > Now to the solution:
> > You say you're using release alpha-5-1. If you open the model in
> > CayenneModeller, you may notice that the ObjRelationships have an
> > additional column on the right of their specification, titled "Delete
> > rule". In a5-1, the actual implementation of that is disabled (some
> > bugs that mucked up constraints ... tested initially on mysql, committed
> > to cvs, then discovered it failed on Oracle which actually has
> > constraints. Bah humbug).
> >
> > If you get the nightly build, the implementation has been sorted out.
> > So, what you'd do is set the relationship from ProjectUser to User to be
> > Nullify (actually, that's the default). Then, your for loop would look
> > like this (parentheses might be wrong):
> >
> > for (int i=0; i<projectuserss.size(); i++) {
> > ctxt.deleteObject(((Projectusers)projectuserss.get(i)));
> > }
> >
> > The delete rule is fired when you delete the ProjectUser. It looks at
> > all of the relationships from ProjectUser to other ObjEntities. For
> > nullify, it looks at the reverse relationship (user projectusersArray in
> > this case). If it's toOne, it is set to null. If to-Many (your case),
> > the object being deleted will be removed from that relationship. If
> > there is no reverse relationship, nothing happens. The other rules are
> > Cascade (if you set this relationship to cascade, the User would be
> > deleted) and Deny, which throws an exception when you try to delete if
> > the destination has any objects.
> >
> > Let me know if you need more help on this.. I'm planning on writing
> > docos on it, but haven't yet had the time (actually, more like "not had
> > the inclination", but lack of time sounds better :-))
> >
> > Craig Miskell
> >
> >
> > On Wed, 2003-01-15 at 12:27, Fan, Bill (AP - Australia) wrote:
> >> Hi All,
> >>
> >> I'm having problem to use the X.removeFromYArray(y) function to delete
> >> the 1:n relationship records in the database. I'm using tomcat 4.1.17
> >> + Struts 1.1 + Cayenne-1.0a5-1.
> >>
> >> It is a project issue management system. There are 4 tables in the
> >> user management section - Project, Users, Role & ProjectUsers. The
> >> tables are defined as following (in brief):
> >>
> >> Project:
> >> ProjectId int PK
> >> ProjectName varchar(100)
> >>
> >> Users: (oops, can't use User in MSSQL, don't get confused below... )
> >> UserId int PK
> >> Login varchar(50)
> >> Password varchar(20)
> >>
> >> Role:
> >> RoleId int PK
> >> RoleDesc varchar(50)
> >>
> >> ProjectUsers:
> >> ProjectId int FK
> >> UserId int FK
> >> RoleId int FK
> >>
> >> ProjectUsers table holds all the information how the user can access
> >> the system. When I come to the section to edit/modify the user roles,
> >> I need to delete the records in this table for a user related to a
> >> particular project, then add the new ones. The logic related to the
> >> deletion process is as following:
> >>
> >> // 1. get the user object
> >> Users users = getUsers(ctxt, login);
> >>
> >> // 2. get the all related projectuser objects(regardless what
> >> project for now)
> >> List projectuserss = user.getProjectusersArray();
> >>
> >> // 3. iterating through the projectusers list and remove them: for
> >> (int i=0; i<projectuserss.size(); i++)
> >>
> >> user.removeFromProjectusersArray((Projectusers)projectuserss.get(i));
> >>
> >> // 4. finally, commit the changes
> >> ctxt.commitChanges(Level.WARN);
> >>
> >> No matter what I did, just can't see the DELETE statement generated by
> >> Cayenne from the tomcat running console, and the database records are
> >> not removed obviously.
> >>
> >> The users object and the related projectuserss list returned by the
> >> statements can be verified they are all correct. I've tried to set the
> >> users object consistence state by using
> >> users.setPersistenceState(PersistenceStte.MODIFIED) right after I get
> >> the users object, eventhough it is not the case in the
> >> RemovePaintingFroGalleryAction example.
> >>
> >> On the other hand, the users.addToProjectusersArray(projectusers)
> >> function is working perfectly (I've added lot of duplicated records ;-
> >> )
> >>
> >>
> >> What I'm doing wrong here? Can anyone point me to the right direction?
> >>
> >>
> >> Thanks for your help!
> >>
> >> Bill
> >>
> >>
> >>
> >>
> >>
> >>
> >>
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