/* UPDATE FROM via PP rule. */

PROCEDURE Main()
   LOCAL aStruct

   FErase( "mas.dbf" )
   FErase( "del.dbf" )

   /* Master: id, total. Initially totals are zero. */
   aStruct := { ;
      { "ID",    "N", 4, 0 }, ;
      { "NAME",  "C", 8, 0 }, ;
      { "TOTAL", "N", 8, 2 } }
   dbCreate( "mas.dbf", aStruct )
   USE mas.dbf NEW EXCLUSIVE ALIAS mas
   dbAppend() ; FieldPut(1, 1) ; FieldPut(2, "Alice") ; FieldPut(3, 0)
   dbAppend() ; FieldPut(1, 2) ; FieldPut(2, "Bob")   ; FieldPut(3, 0)
   dbAppend() ; FieldPut(1, 3) ; FieldPut(2, "Carol") ; FieldPut(3, 0)
   dbCommit()
   dbCloseArea()

   /* Delta: same id, amount to apply. Sorted by id. */
   aStruct := { ;
      { "ID",  "N", 4, 0 }, ;
      { "AMT", "N", 8, 2 } }
   dbCreate( "del.dbf", aStruct )
   USE del.dbf NEW EXCLUSIVE ALIAS del
   dbAppend() ; FieldPut(1, 1) ; FieldPut(2, 100)
   dbAppend() ; FieldPut(1, 2) ; FieldPut(2, 200)
   dbAppend() ; FieldPut(1, 3) ; FieldPut(2, 300)
   dbCommit()
   dbCloseArea()

   /* Re-open both, sorted on id. */
   USE mas.dbf NEW EXCLUSIVE ALIAS mas
   USE del.dbf NEW EXCLUSIVE ALIAS del
   SELECT mas

   ? "--- before UPDATE FROM ---"
   dbGoTop()
   DO WHILE !Eof()
      ? "  ", FieldGet(1), AllTrim(FieldGet(2)), FieldGet(3)
      dbSkip()
   ENDDO

   ? ""
   ? "--- UPDATE FROM del ON id REPLACE total WITH del->amt ---"
   dbGoTop()
   UPDATE FROM del ON id REPLACE total WITH del->amt

   ? ""
   ? "--- after UPDATE FROM ---"
   dbGoTop()
   DO WHILE !Eof()
      ? "  ", FieldGet(1), AllTrim(FieldGet(2)), FieldGet(3)
      dbSkip()
   ENDDO
   ? "(expect: 1 Alice 100, 2 Bob 200, 3 Carol 300)"

   SELECT del
   dbCloseArea()
   SELECT mas
   dbCloseArea()
   FErase( "mas.dbf" )
   FErase( "del.dbf" )
   ? "DONE"
   RETURN