code: protected Query[] buildPrefetchQueries(Collection owners, Collection children)
      {
          ClassDescriptor cld = getOwnerClassDescriptor();
          Class topLevelClass = getBroker().getTopLevelClass(cld.getClassOfObject());
          BrokerHelper helper = getBroker().serviceBrokerHelper();
          Collection queries = new ArrayList(owners.size());
          Collection idsSubset = new HashSet(owners.size());
          Object[] fkValues;
          Object owner;
          Identity id;
  
          Iterator iter = owners.iterator();
          while (iter.hasNext())
          {
              owner = iter.next();
              fkValues = helper.extractValueArray(helper.getKeyValues(cld, owner));
              id = getBroker().serviceIdentity().buildIdentity(null, topLevelClass, fkValues);
              idsSubset.add(id);
              if (idsSubset.size() == pkLimit)
              {
                  queries.add(buildPrefetchQuery(idsSubset));
                  idsSubset.clear();
              }
          }
  
          if (idsSubset.size() > 0)
          {
              queries.add(buildPrefetchQuery(idsSubset));
          }
  
          return (Query[]) queries.toArray(new Query[queries.size()]);
      }
docs: Build the multiple queries for one relationship because of limitation of IN(...)
  
  @param owners Collection containing all objects of the ONE side