SAP Place

If you've done a bit of substitutions or validations, tocdes GBB1 and GBB0, respectively, then you might've encountered a case where you need to retrieve another object's details, e.g. get parent's WBS element's cost center. You might think that you'll only need to get the object's ID or number and work from there, but remember that the details may not have been committed to the database yet.

There are a couple of direct ways to achieve this:
1. Use matrix parameter
Set this feature when you define your exit in your custom copy of RGGBR000/RGGBS000. There is an example to capture this in the sample programs already, but basically it is to capture the FI document items (single BKPF entry & multiple BSEG entries).

2. Use SAP standard function modules to read from the buffer
SAP standard function modules related to the objects in validations/substitutions generally have a function module that will enable you to read from the buffer, instead from the database.