Pathmaker Programming Guide

Controlling Default Screen Layout
Creating Requesters
5–16 067868 Tandem Computers Incorporated
The HEADING and VALUES clauses are fully described in the Data Definition
Language (DDL) Reference Manual.
The OCCURS and OCCURS DEPENDING ON clauses have some special
considerations when you use them in Pathmaker application development:
OCCURS and OCCURS DEPENDING ON clauses cannot be nested.
A subordinate group or field can inherit OCCURS or OCCURS DEPENDING ON
dimensions from a higher level declaration. In the following example XXX, YYY,
and ZZZ are repeated 3 times:
01 AA.
02 BB OCCURS 3 TIMES.
03 XXX PIC X(10).
03 CCC.
04 YYY PIC 9(6).
04 ZZZ PIC X(30).
OCCURS and OCCURS DEPENDING ON items can be presented on the
application screen in either compressed, uncompressed, or tabular format.
Every occurrence of an OCCURS or OCCURS DEPENDING ON data item must fit
on a single page of the logical screen.
For TRNS requesters, design the IPC reply message with the screen display in
mind.
For DB requesters, do not create DDL records with large OCCURS clauses.
The next few points refer to this DDL definition to illustrate rules for passing
parameters that use the OCCURS clause:
DEF Parent.
02 Group1 OCCURS 3 TIMES.
03 Child1 PIC X(10).
02 Group2.
03 Child2 PIC X(3).
END
You can pass the entire definition (that is, 01 level items) to another requester or to
a service; therefore, you can pass PARENT.
You cannot pass lower level fields (that is, below 01 level) influenced by an
OCCURS clause to either a requester or to a service because the reference is
ambiguous. You cannot pass CHILD1 because the specific instance of CHILD1
that you intend to pass is not clear.
You can pass lower level fields that are not influenced by an OCCURS clause to a
service. For example, you can pass CHILD2; there is no ambiguity in this case.