By removing the composite key and making the dataId field be the key the problem was resolved (both query and criteria work). I like to understand what was the cause of the problem though. I am new to hibernate, anyone knows enough about hibernate to comment on it?

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From: Rakhshani, Mehdi (GXS)
Sent: Tuesday, September 26, 2006 1:12 PM
To: 'hibernate-issues@lists.jboss.org'
Subject: RE: Query.list() returns one item (as expected) but that item is null (which is unexpected)

I have a simple query that when I execute in sqlplus returns one record as expected. When I run the same query using hibernate and java, I get a list back which has one record, but that record is null.

I wrote the same search using Criteria and hibernate complains that the column name cannot be resolved. Whether I use the “name” attribute or the “column” attribute of the property it makes no difference.

Hibernate 3.1: 1,971,632 hibernate3.jar, Windows XP, Oracle DB

HBM snippet:

<hibernate-mapping package="com.gxs.iefe.alias">

      <class

            name="AliasTable"

            table="IEFE.ALIAS_TABLE"

      >

            <meta attribute="sync-DAO">false</meta>

            <composite-id name="id" class="AliasTablePK">

                  <key-property

                        name="owningSystem"

                        column="OWNING_SYSTEM"

                        type="string"

                  />

                  <key-property

…

Code snippet using query:

            q = theSession.createQuery(

"from AliasTable where OWNING_SYSTEM = :sys and OWNING_ACCOUNT is null and OWNING_USER_ID is null and TABLE_NAME = :tbl" );

            q.setString( "sys", theOwner.getSystem() );

            q.setString( "tbl", theTable );

// Using q.uniqueResult() produces the same behavior

            List anAliasTableList = q.list();

if ( null == anAliasTableList || 0 == anAliasTableList.size() )

throw new Exception( “Null list“ );

            // Code that verifies list size has been removed. “Null list element” is thrown.

            anAliasTable = (AliasTable)anAliasTableList.get( 0 );

if ( null == anAliasTable )

throw new Exception( “Null list element” );

Code snippet using criteria:

            Criteria aCriteria = theSession.createCriteria( AliasTable.class );

                        // Specifying neither property name nor property column works: could not resolve property: owningSystem of: com.gxs.iefe.alias.AliasTable

//aCriteria.add( Restrictions.eq( "OWNING_SYSTEM", theOwner.getSystem() ) );

            aCriteria.add( Restrictions.eq( "owningSystem", theOwner.getSystem() ) );

            aCriteria.add( Restrictions.isNull( "owningAccount" ) );

            aCriteria.add( Restrictions.isNull( "owningUserId" ) );

            aCriteria.add( Restrictions.eq( "tableName", theTable ) ); 

// Retrieve the data

            List anAliasTableList = aCriteria.list();

Any idea why?