iSeries (AS/400) Cobol Subfile Programming

Introduction

It is hard to imagine application development without the use of subfiles. This course provides tuition in the practical use of subfiles, and how to code them within COBOL/400 programs.

What you will learn

On completion of this course, you will be able to:

• Identify the styles of subfiles available, and choose the right subfile for an application.
• Code a load-all subfile.
• Code a page by page subfile.
• Code a single page subfile.
• Code a data entry subfile.
• Enhance subfile programs.
• Code a message subfile.
• Code a subfile window application.

Who should attend

Experienced COBOL/400 programmers developing subfile applications for use on the iSeries.

Pre-requisites

Attendees should attend either the iSeries COBOL PROGRAMMING course, or the iSeries COBOL CROSSOVER course prior to attending course. This should then be followed with a period of practical work using COBOL/400. Delegates need to have a good practical knowledge of SDA, PDM and SEU. Delegates who have the necessary COBOL/400 experience, including the use of the iSeries extensions, may also attend this course.

Course content

• The concepts of subfiles.
• Subfile record formats.
• Subfile loading techniques.
• Relative record number processing.
• Declaring a display file to use a subfile.
• The subfile record and subfile control record.
• Keywords on the subfile control record.
• Subfile design using SDA.
• Cobol processing for subfiles.
• The load all subfile program logic.
• Loading and processing a load all subfile.
• The expanding subfile technique.
• Coding page up and page down.
• What to do at end of file.
• Avoiding the empty roll.
• Loading and processing an expanding subfile.
• When to use single page subfiles.
• Single page subfile program logic.
• Coding subfiles in windows.
• DDS keywords for window subfiles.
• Displaying windows from a called program.
• Subfiles for data entry.
• Subfile validation and database updates.
• Reading sequentially through a subfile.
• Coding a message subfile.
• CL programs for use with message subfiles.
• Using message subfiles in Cobol.
• Journalling and commitment control with subfiles.

Materials

A course manual with supporting documentation is provided. Participants on this course will develop several subfile based applications, using each of the three subfile programming styles. Delegates may bring a quarter inch tape cartridge to backup the materials developed on this course for further reference.

Schedule - Dates on Request