* @see com.antlersoft.query.SetExpression#evaluate(com.antlersoft.query.DataSource)
*/
public Enumeration evaluate(DataSource source) {
Vector tmp=new Vector( 1);
ILDB db=(ILDB)source;
Object q=db.findObject( DBClass.CLASS_BY_NAME_INDEX, _className);
if ( q!=null)
tmp.addElement( q);
for ( Iterator i=_set.iterator(); i.hasNext() && q==null;)
{
q=db.findObject( DBClass.CLASS_BY_NAME_INDEX, ((String)i.next())+"."+_className);