Hi Madan,
Check this info.
Parametere Id is the one which holds the memory for the particular field. when we need to pass the the field from one screen to another use the parameter Id.
The SAP Memory is a user-specific memory area of the application server, which is accessed by all main sessions of a user session at once. ABAP programs have access to SPA/GPA parameters stored in the SAP Memory (also called SET/GET parameters).
Eg. Of how to use Set parameter
you can give value of variable (dobj) to parameter ID 'pid'. This will store value in SAP memory
SET PARAMETER ID pid FIELD dobj.
When you want to use that value stored in SAP memory
you can use GET parameter.
GET PARAMETER ID pid FIELD dobj.
To fill the input fields of a called transaction with data from the calling program, you can use the SPA/GPA technique. SPA/GPA parameters are values that the system stores in the global, user-specific SAP memory. SAP memory allows you to pass values between programs. A user can access the values stored in the SAP memory during one terminal session for all parallel sessions. Each SPA/GPA parameter is identified by a 20-character code. You can maintain them in the Repository Browser in the ABAP Workbench. The values in SPA/GPA parameters are user-specific.
ABAP programs can access the parameters using the SET PARAMETER and GET PARAMETER statements.
To fill one, use:
SET PARAMETER ID <pid> FIELD <f>.
This statement saves the contents of field <f> under the ID <pid> in the SAP memory. The code <pid> can be up to 20 characters long. If there was already a value stored under <pid>, this statement overwrites it. If the ID <pid> does not exist, double-click <pid> in the ABAP Editor to create a new parameter object.
To read an SPA/GPA parameter, use:
GET PARAMETER ID <pid> FIELD <f>.
This statement fills the value stored under the ID <pid> into the variable <f>. If the system does not find a value for <pid> in the SAP memory, it sets SY-SUBRC to 4, otherwise to 0.
To fill the initial screen of a program using SPA/GPA parameters, you normally only need the SET PARAMETER statement.
The relevant fields must each be linked to an SPA/GPA parameter.
On a selection screen, you link fields to parameters using the MEMORY ID addition in the PARAMETERS or SELECT-OPTIONS statement. If you specify an SPA/GPA parameter ID when you declare a parameter or selection option, the corresponding input field is linked to that input field.
Check this link.
http://help.sap.com/saphelp_47x200/helpdata/en/f5/6a853c61c5140ee10000000a11405a/frameset.htm
Hope this resolves your query.
Reward all the helpful answers.
Regards
Bluesky
