SAP Note 28007 - FI-SL: Defining unique index on object tables

Symptom:

Important:
This note is only relevant for customers who defined FI-SL tables containing objects in Release 2.1 and are working productively with these tables in this or a later release.

For reasons of data consistency, a unique index should be defined using the object number of the respective FI-SL table.
This technically ensures that no double object numbers are written to the FI-SL object table.

Cause and prerequisites

If no unique index is defined for the object table, it can happen under certain special circumstances that double object numbers are written to the object table, namely when the current number level of the number range object GL_OBJECT is reset by mistake (manually or by a transport).
As a result, the line item record and the respective summary record also would be updated differently. Line item record and summary record would no longer "match", which would lead to data inconsistency.

Solution
1) Using transaction SE11, create a unique index for the FI-SL object table in question, which contains the fields
MANDT
OBJNR.

Do not forget to activate the UNIQUE index indicator.
Then please activate this index in the ABAP/4 Dictionary.
2) Create the index in question in the database using transaction SE14.

If activating the index terminates with the message that the index cannot be defined as UNIQUE, this is an indication that double object numbers have already been assigned. In this case, please contact the SAP Hotline.