Inconsistent results with many-to-one.

vloh · **Posted:** Sun Jan 04, 2004 12:54 pm

Hi,

I am using Hibernate 2.0.3 with DB2 8.1.3.

I came across a very strange behaviour with the many-to-one tag.

I used the following stand-alon example and it works fine:

Parent.hbm.xml:
--------------------
<hibernate-mapping>
<class name="hibtest.Parent" table="parent">
<id name="parentId" column="parentid" >
<generator class="assigned" />
</id>
<property name="parentName" type="string" />
<bag name="children"
inverse="true"
lazy="false"
order-by="childId"
cascade="all">
<key column="parentId"/>
<one-to-many class="hibtest.Child"/>
</bag>
</class>
</hibernate-mapping>

Child.hbm.xml:
------------------
<hibernate-mapping>
<class name="hibtest.Child" table="child">
<id name="childId" column="childid" >
<generator class="assigned" />
</id>
<property name="childName" type="string" />
<many-to-one name="Parent" column="parentId" not-null="true" />
</class>
</hibernate-mapping>

Database query:
---------------------
List list = session.find("from Child where childName = 'Boneeto'");

The above gets me the result I expected. i.e. if:
Table Parent
----------------
parentId: AAA, parentName: aaa
parentId: BBB, parentName: bbb
parentId: CCC, parentName: ccc

Table Child
--------------
parentId: AAA, childId: zzz, childName: Boneeto
parentId: BBB, childId: yyy, childName: Boneeto

then I get the Parents: AAA and BBB.

However, when I adapted to it to my own requirements:


<hibernate-mapping>
<class name="UserRoleRelation" table="userrolerelation">
<id name="labsRoleId" column="labsRoleId" >
<generator class="assigned" />
</id>
<many-to-one name="LabsUser" column="labsUserId" not-null="true" /> 
</class>
</hibernate-mapping>

I only get the first set of LabsUser (Parent) no matter how many matching records in LabsUser and UserRoleRelation.

Any ideas what could be wrong?

Regards,
Vincent.

emmanuel · **Posted:** Sun Jan 04, 2004 2:26 pm

Full mapping and data in your DB ?

vloh · **Posted:** Sun Jan 04, 2004 10:56 pm

The data in table LabsUser (the Parent) contains:

Code:

LABSUSERID  FIRSTNAME             LASTNAME
----------  --------------------  --------------------
robi        Robert                HAUF
schur       Frank                 SCHUR
razali      Razali                AHMAD
loh         Vincent               LOH
duncan      Tim                   DUNCAN
garnett     Kevin                 GARNETT
robinson    David                 ROBINSON
allen       Ray                   ALLEN
stockton    Joh                   STOCKTON

The full mapping for LabsUser.hbm.xml is:

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
   "-//Hibernate/Hibernate Mapping DTD//EN"
   "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping>
   <class name="hibtest.LabsUser" table="labsuser">
      <id name="labsUserId" column="labsuserid">
          <generator class="assigned"/>
      </id>
      <property name="firstName" type="string" />
      <property name="lastName" type="string" />
      <bag name="userRolesList" inverse="true" lazy="false" cascade="all" order-by="labsRoleId">
         <key column="labsUserId" />
         <one-to-many class="hibtest.UserRoleRelation" />
      </bag>
   </class>
</hibernate-mapping>

The data in table UserRoleRelation (the Child) contains:

Code:

LABSROLEID  LABSUSERID
----------  ----------
CR          loh
AD          loh
AP          loh
PC          loh
AD          robi
AP          robinson
PC          duncan
AP          stockton
PC          garnett
PC          allen

The full mapping for UserRoleRelation.hbm.xml is:

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
   "-//Hibernate/Hibernate Mapping DTD//EN"
   "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping>
   <class name="hibtest.UserRoleRelation" table="userrolerelation">
      <id name="labsRoleId" column="labsRoleId" >
         <generator class="assigned" />
      </id>
      <many-to-one name="LabsUser" column="labsUserId" not-null="true" />
   </class>
</hibernate-mapping>

When I execute the following:

Code:

Session session = null;

try {
   session = sf.openSession();

   List lp = session.find("from UserRoleRelation where labsRoleId like 'PC'");

   for (int i = 0; i < lp.size(); i++) {
      System.out.println(((UserRoleRelation) lp.get(i)).getLabsUser().getLabsUserId());
   }
} catch (Exception e) {
   e.printStackTrace();
} finally {
   if (session != null)
      session.close();
}

It retrieves only the LabUserId = 'loh' even though there are 4 items in the list.

emmanuel · **Posted:** Mon Jan 05, 2004 12:27 pm

Hum, as you said to Hibernate, LABSROLEID is a primary key, and thus is unique in the table... So it will read the first result and stop. You misdeclare your primary key