code: private String toSQLClause(SelectionCriteria c, ClassDescriptor cld)
      {
          String colName = toSqlClause(c.getAttribute(), cld);
          return colName + c.getClause() + " ? ";
      }
docs: Answer the SQL-Clause for a SelectionCriteria
  
  @param c SelectionCriteria
  @param cld ClassDescriptor