Non-Decomposed m:n Mappings - Question

[JS...@vinu.edu]

I'm trying to do a m:n mapping with non-decomposed. I have a class called 
applicant that references multiple program classes. But all applicant 
objects can reference the same program object. So if I have ten applicant 
objects and each applicant object references five program objects. Then 
out of the ten applicant objects four of them may be referencing the same 
program object. So when I load up an applicant object it will have a 
vector of program object I can access and update. But I do not want that 
applicant object to be able to delete or update the programs objects, 
because multiple applicant object may reference that same program. I just 
want to be able to remove the program objects from that applicant objects 
vector. If this makes sense can someone tell me where when I try to load x 
number of program objects from the database and set them in the applicant 
objects vector I get nothing. Right before I add the program object to the 
vector I try to print the programs name and it show nothing. But if I 
print the name right after I get them from the db the they are correct. 
Basically it's getting them from the database, but when I leave the scope 
of the method below it's like the reference if cleared out. Can someone 
tell me why this is. I've attached the user xml and the code that I'm 
using below:


public void processProgramData(java.util.Vector prog_vec, 
javax.servlet.http.HttpServletRequest req, java.util.Vector err) {
        if(req.getParameter(this.PROGRAMS) != null){
            if(req.getParameterValues(this.PROGRAMS).length > 0){
                String [] prog_ray = 
req.getParameterValues(this.PROGRAMS);
                prog_vec.clear();
                com.vu.applynow.applicant.Program program_obj = new 
com.vu.applynow.applicant.Program();
                for(int i=0;i < prog_ray.length;i++){
                    if(this.getProgram(prog_ray[i], program_obj)){
// If i print program_obj.getName() here it show blank, like the name 
variable object in the program class has been cleared
                        System.out.println("Object: " + 
program_obj.getName());
                        prog_vec.add(program_obj);
                    }
                }
            }
        }
    }
 
    private boolean getProgram(String id, 
com.vu.applynow.applicant.Program program) {
        org.odmg.Transaction tx = null;
        try{
            tx = this.odmg.newTransaction();
            tx.begin();
            org.odmg.OQLQuery query = this.odmg.newOQLQuery();
            query.create("select program from " + 
com.vu.applynow.applicant.Program.class.getName() + " where id = $1");
            query.bind(id);
            org.odmg.DList result = (org.odmg.DList) query.execute();
            program = (com.vu.applynow.applicant.Program) result.get(0);
            tx.commit();
// If I print program.getName() it shows............
            return true;
        }catch(org.odmg.QueryException e){
            tx.abort();
            return false;
        }catch(java.lang.IndexOutOfBoundsException e){
            tx.abort();
            return false;
        }
    }




Here's the xml........


<class-descriptor class="com.vu.applynow.applicant.Applicant" 
table="Applicant"> 
    <field-descriptor name="id" column="id" jdbc-type="INTEGER" 
primarykey="true" autoincrement="true"></field-descriptor>
    <field-descriptor name="term" column="term" 
jdbc-type="VARCHAR"></field-descriptor>
    <field-descriptor name="term_year" column="term_year" 
jdbc-type="INTEGER"></field-descriptor>
    <field-descriptor name="status" column="status" 
jdbc-type="VARCHAR"></field-descriptor>
    <field-descriptor name="campus" column="campus" 
jdbc-type="VARCHAR"></field-descriptor> 
    <field-descriptor name="expelled" column="expelled" 
jdbc-type="BIT"></field-descriptor> 
    <field-descriptor name="probation" column="probation" 
jdbc-type="BIT"></field-descriptor> 
    <field-descriptor name="felony" column="felony" 
jdbc-type="BIT"></field-descriptor> 
    <field-descriptor name="comments" column="comments" 
jdbc-type="VARCHAR"></field-descriptor>
 
    <field-descriptor name="identif_id" column="identif_id" 
jdbc-type="INTEGER"></field-descriptor>
    <reference-descriptor name="identif" 
class-ref="com.vu.applynow.applicant.Identification"  auto-retrieve="true" 
 auto-update="true"  auto-delete="true">
    <foreignkey field-ref="identif_id"/>
    </reference-descriptor>
 
    <field-descriptor name="major_id" column="major_id" 
jdbc-type="INTEGER"></field-descriptor>
    <reference-descriptor name="major" 
class-ref="com.vu.applynow.applicant.Major"  auto-retrieve="true" 
auto-update="false"  auto-delete="false">
    <foreignkey field-ref="major_id"/>
    </reference-descriptor>
 
    <field-descriptor name="guardian_id" column="guardian_id" 
jdbc-type="INTEGER"></field-descriptor>
    <reference-descriptor name="guardian" 
class-ref="com.vu.applynow.applicant.Guardian"  auto-retrieve="true" 
auto-update="true"  auto-delete="true">
    <foreignkey field-ref="guardian_id"/>
    </reference-descriptor>
 
    <field-descriptor name="highschool_id" column="highschool_id" 
jdbc-type="INTEGER"></field-descriptor>
    <reference-descriptor name="highschool" 
class-ref="com.vu.applynow.applicant.HighSchool"  auto-retrieve="true" 
auto-update="true"  auto-delete="true">
    <foreignkey field-ref="highschool_id"/>
    </reference-descriptor>
 
    <field-descriptor name="signature_id" column="signature_id" 
jdbc-type="INTEGER"></field-descriptor>
    <reference-descriptor name="signature" 
class-ref="com.vu.applynow.applicant.Signature"  auto-retrieve="true" 
auto-update="true"  auto-delete="true">
    <foreignkey field-ref="signature_id"/>
    </reference-descriptor>
 
    <collection-descriptor name="colleges" 
element-class-ref="com.vu.applynow.applicant.College" orderby="id" 
auto-retrieve="true"  auto-update="true"  auto-delete="true">
    <inverse-foreignkey field-ref="applicant_id"/>
    </collection-descriptor>
 
    <collection-descriptor name="dualenrolls" 
element-class-ref="com.vu.applynow.applicant.DualEnroll" 
auto-retrieve="true" auto-update="false" auto-delete="false" 
indirection-table="AppToDE">
    <fk-pointing-to-this-class column="applicant_id"/>
    <fk-pointing-to-element-class column="dualenroll_id"/>
    </collection-descriptor>
 
    <collection-descriptor name="goals" 
element-class-ref="com.vu.applynow.applicant.Goal" auto-retrieve="true" 
auto-update="false" auto-delete="false" indirection-table="AppToGoal">
    <fk-pointing-to-this-class column="applicant_id"/>
    <fk-pointing-to-element-class column="goal_id"/>
    </collection-descriptor>
 
    <collection-descriptor name="programs" 
element-class-ref="com.vu.applynow.applicant.Program" auto-retrieve="true" 
auto-update="false" auto-delete="false" indirection-table="AppToProgram">
    <fk-pointing-to-this-class column="applicant_id"/>
    <fk-pointing-to-element-class column="program_id"/>
    </collection-descriptor>
 
</class-descriptor>



<class-descriptor class="com.vu.applynow.applicant.Program" 
table="Programs"> 
    <field-descriptor name="id" column="id" jdbc-type="INTEGER" 
primarykey="true" autoincrement="true"></field-descriptor>
    <field-descriptor name="name" column="name" 
jdbc-type="VARCHAR"></field-descriptor>
</class-descriptor>


Justin A. Stanczak
Web Manager
Shake Learning Resource Center
Vincennes University
(812)888-5813

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