code: private boolean isOrdered(FieldDescriptor[] flds, String[] pkFieldNames)
      {
          if((flds.length > 1 && pkFieldNames == null) || flds.length != pkFieldNames.length)
          {
              throw new PersistenceBrokerException("pkFieldName length does not match number of defined PK fields." +
                      " Expected number of PK fields is " + flds.length + ", given number was " +
                      (pkFieldNames != null ? pkFieldNames.length : 0));
          }
          boolean result = true;
          for(int i = 0; i < flds.length; i++)
          {
              FieldDescriptor fld = flds[i];
              result = result && fld.getPersistentField().getName().equals(pkFieldNames[i]);
          }
          return result;
      }
docs: Checks length and compare order of field names with declared PK fields in metadata.