What is set parameter and get parameter?
We can pass data to a called program using SPA/GPA parameters. SPA/GPA parameters are field values saved globally in memory. Each parameter is identified by a three-character code: you can define these parameters in the object browser by selecting Other objects on the first screen. The SPA/GPA storage is user-specific and valid throughout all the user's sessions.by using the SET PARAMETER or GET PARAMETER statements
These statements let you store and retrieve SPA/GPA values from an ABAP/4 program. If the selection screens for the two transactions do not share the same required fields, use these statements to store screen fields explicitly by name.
Before calling the new transaction from a PAI module, store the caller transaction's fields under one name:
SET PARAMETER ID 'RID' FIELD <FIELD NAME1>.
The system stores the value in <field name1> in the SPA parameter 'RID'. The three-character identifier 'RID' must be defined in the SAP table TPARA. If the SPA parameter 'RID' already contains a value, the SET PARAMETER statement overwrites it (with the contents of <FIELD NAME1>).
In the PBO module for the called transaction, retrieve the fields under the other name:
GET PARAMTER ID 'RID' FIELD <FIELD NAME2>.
