PROGRAMMING IN COBOL/400: 2nd Edition

Chapter 14. INTERACTIVE PROGRAMMING

CHAPTER OBJECTIVES

Upon completion of this chapter, you should be able to

• Describe design considerations when developing screen layouts.

• Explain how a display file is used in an interactive program.

• Demonstrate the ability to create and run an interactive program that uses a display file.

BATCH VERSUS INTERACTIVE PROCESSING

BATCH PROCESSING

In previous chapters, sample problems used batch processing concepts. Batch processing means transactions are first gathered together, and then all transactions are processed as a group during one complete job. For example, businesses typically collect payroll data over a period of time and produce payroll checks for each pay period at one time. This is an example of batch processing, that is, collecting and holding all data until output is requested or needed, and then processing the batch all at once.

Several methods can be used for collecting data in a batch environment. In one such method, data are entered on a computer that is not even connected to the main computer system. This type of data entry for future batch processing is called an off-line operation. For example, payroll data might be entered at several corporate sites and then transmitted via telephone lines to the computer at corporate headquarters once a week so that paychecks can be produced in a batch processing operation.

Since batch processing does not process data immediately as it is transacted, users may not be getting the output from the computer ...