Urgent : setNull in query is not equal to "is NULL" ?

Question

Hi there,
I've got a finder on my CMP EJB bean. This finder has been generated by VAJ 4.0 JDK1.2.2. Im running against DB2 v
The implementation look like this :
public EJSFinder findBysomething(java.lang.Long arg1, java.lang.Long arg2, java.lang.Integer arg3) throws java.rmi.RemoteException, javax.ejb.FinderException {
     ResultSet rs = null;
     PreparedStatement ps = null;
     EJSJDBCFinder result = null;
     try {
          preFind();
          ps = getMergedPreparedStatement(somestatement);
          for (int i=0; i<(6*getMergedWhereCount()); i=i+6) {
               // Injecting "java.lang.Long arg1"
               if (arg1 == null) ps.setNull(1, -5); else ps.setLong(i+1, arg1.longValue());
               // Injecting "java.lang.Long arg2"
               if (arg2 == null) ps.setNull(2, -5); else ps.setLong(i+2, arg2.longValue());
               // Injecting "java.lang.Integer arg3"
               if (arg3 == null) ps.setNull(3, 4); else ps.setInt(i+3, arg3.intValue());
          rs = ps.executeQuery();
          result = new EJSJDBCFinder(rs, this, ps);
     } catch (Exception exc) {
          try {
               if (rs != null) rs.close();
          } catch (SQLException sqlExc) {}
          if (ps != null) super.returnPreparedStatement(ps);
          throw new EJSPersistenceException("blabla");
     return result;
}keep in mind that i have changed the code to make it look simpler, so no need for syntax error checking.
The problem is the 'ps.setNull' method. It seems that when it sets it the sql looks like "somevariable = null" which is (as far as i know) always false. What i want the sql to be is "somevariable is NULL" which can be true or false.
Because the "somevariable = null" is always false the query does not return anything. If i run the same query with "somevariable is NULL" then i get records returned. Ive also tried implementing a session bean with a dynamic built query where it works fine, like this :
     if (somevar != null) {
          sqlbuffer.append(" and t1.somevar=?");
     } else {
          sqlbuffer.append(" and t1.somevar is NULL ");          
     }How do implement it correctly in the finder ?
thanks in advance.

Answer 1

You might get a better answer in Enterprise Beans. There isn't much similarity between JDBC and CMP.
However, as far as I know you can't do that with CMP. Although that might depend on your container.
You can however go around it higher up in a servlet and do a direct query (varying the SQL per the arguments) and return the ids of the entities. Then you use that to retrieve the correct entities and create the collection that you need.