Essentials of Subfile Programming and Advanced Topics in Rpg

Today programs and systems are increasingly screen-based and interactive. Subfiles are the AS/400 tool that lets you display lists of data on the screen for user interaction. Your knowledge of subfiles will increase your marketability and prepare you to move to the next level with confidence. Essentials of Subfile Programming and Advanced Topics in RPG teaches you to design and program subfiles, offering step-by-step instructions and real-world programming exercises that build from chapter to chapter. You’ll learn to design and create subfile records; load, clear, and display subfiles; develop display-file code and RPG code for interactive file maintenance; create pop-up windows for user interaction; and support users with advanced prompting features and Help screens. The book will further help you link RPG programs and database files, including using the record format level identifier and the OVRDBF (Override with Database File) and OPNQRYF (Open Query File) comm! ands; mine the rich store of data in the file-information and program-status data structures; handle errors, including using the *PSSR subroutine, the INFSR keyword and LO indicators, error messages, and error logs; improve data integrity by using journaling and commitment control; and manage program-to-program communications, especially via the power of AS/400 data queues. Three useful appendices cover issues of programming standards and style, testing and debugging programs, and using Screen Design Aid (SDA).