General

The Main Program is a simple “Type 1” (Executable) ABAP program/report and can be created or changed via the transaction /BTR/DIFFUSER, or the standard SAP transaction SE38. For ease we recommend the transaction /BTR/DIFFUSER. Within the Main program, the basic structure of a custom ABAP report is:

• Declaration – Declaration of working variables, include files, type declarations and so forth
• Selection Screen – Parameter screen definition of select-options and parameters
• Start-Of-Selection Event – Program Initialization
• Interval Processing Subroutine – Initial Data Restriction logic and Processing logic
• Collating Interval Subroutine – Collation logic to combine interval results (This is optional)

Note that there is no mention of result presentation in the Main Program; this is implemented in the Transformation program. This means that you should not do the following in the Main program:

• Use the WRITE statement for display to the SAP spool or screen (You can of course use the WRITE statement to format data into variables)
• Use the AT USER-COMMAND or AT LINE-SELECTION processing blocks
• Declare headings or text elements that are to be used for presentation
• Perform any sort of presentation logic