Pathmaker Programming Guide

Defining Data for a Pathmaker Project
Preparing for Pathmaker Application Development
2–32 067868 Tandem Computers Incorporated
DDL Enhancements
Enscribe DDL is a major Tandem product that has been enhanced and modified to
work closely with the Pathmaker product. Because of this close association, DDL must
always be accessed through the Pathmaker full screen interface or PMADL when
developing a Pathmaker application.
When you use F1 from the Pathmaker Main Menu or F5 from the Pathmaker Utility
Menu, or when you use PMADL, the dictionary is automatically opened for Shared
Access on the project subvolume. Access the data dictionary for a Pathmaker project
using one of these methods.
After the dictionary is opened, DDL enforces the following concurrency rules:
Only one user can change a Definition or Record at a time.
While a Definition or Record is being changed, no one else may output, delete, or
refer to it.
The Purge command DICT! will purge all Records and Definitions in the
dictionary, even if the dictionary is opened by more than one user.
The following points are guidelines for defining data in DDL with Pathmaker:
Use an edit file to write your DDL code. At the beginning of the file, include the
appropriate command to instruct the DDL compiler to determine if your DDL
statements will produce correct code for the programming language used at your
facility. For example, if COBOL is used, include the ?COBCHECK command at
the beginning of the file. The DDL compiler will check syntax for FORTRAN, TAL
(Tandem Application Language), PASCAL, C, COBOL, and TACL.
The Pathmaker product requires DEFs and RECORDs used in C services to be
compiled by DDL with the CFIELDALIGN_MATCHED2 command. Doing so
ensures that the request and reply IPC elements are compatible with their
counterparts in COBOL services and SCREEN COBOL requesters. As a
consequence of this requirement, field alignment of existing DEFs and RECORDs
could change when they are recompiled with the CFIELDALIGN_MATCHED2
command, making them incompatible with services, clients, requesters, and
database files that use old versions of the DEFs and RECORDs.