The Orders Program orders.4gl
Much of the functionality is identical to that in earlier Tutorial examples. The
  query/add/delete/update of the orders table would be the same as the examples in
  Chapter 4 and Chapter 6. Only append and query are included in this program, for simplicity. The
  add/delete/update of the items table is similar to that in Chapter 8. The
  complete orders program is outlined, with examples of any new
  functionality.