I have a custom table, in which two fields are there 'Available Budget' and 'Balance budget'
If I am going to change available budget from this table, then balance budget is as follows.
Balance Budget = Available budget - Used amount.
Here data is validated against "used amount" which is maintained in another custom table.
Now while updating or creating new entries in sm30 how to validate the above..
I tried using SM30 'Before save event', the data is not getting modified to display in table
please suggest, it will be helpful if sample code is available