Excerpt from First Steps in SAP® S/4HANA Finance by: Janet Salmon and Claus Wild
Continued from Documenting a Migration Part 1
Documenting a migration continued...
Figure 6.2 shows the keys that identify the original line items that have been migrated and the correction postings entered where the totals do not match the sum of the line items. If there is no entry in the MIG_SOURCE field, it means that the document was not migrated but is a new journal entry (the normal case once operations start after conversion).
Figure 6.2: Details of the migration source
There are different types of migration record depending on the data source:
M (Material Ledger only) and A (Asset Accounting only) records represent data from the subledgers that is enriched with the assignment to an account assignment object in Controlling and the reporting dimensions in General Ledger Accounting. These are usually the most granular records.
C (Controlling only) records represent data from Controlling that is enriched by the reporting dimensions in General Ledger Accounting.
F and G (General Ledger Accounting) records represent either data from SAP ERP General Ledger Accounting, which includes the reporting dimensions from FAGLFLEXA, or data from classic General Ledger Accounting that has been enriched to include the relevant reporting dimensions.
Normally, the entries in the totals table are an aggregation of the data in the line item tables (and therefore redundant), meaning that the migration can simply take the data from the totals tables and put it in backup tables (we saw these when we looked at the GLT0 view in Chapter 1) because it can be aggregated on the fly and does not need to be pre-calculated and stored. However, where the sum of the line items is not the same as the totals to be migrated, the system creates a separate document for the difference. This document effectively makes it clear for an auditor that some of the supporting line items for a totals entry are no longer in the system because they have already been archived.
This correction entry accounts for the fact that old line items might have been archived, leaving only the totals for the early years. The correction entries do not include all the reporting dimensions because they can only access the fields in the original totals records. However, they do ensure that your balance sheet and profit and loss statement for the closed periods meet the audit requirements for such data. Depending on the source of the totals difference, you will find entries for S (Controlling), U (Material Ledger) and V (General Ledger Accounting). There may also be errors in the migration process itself, which are documented with source R (reposting/correction).
Before you start, it is important to understand that the migration process will migrate every financial document in the system. It therefore makes sense to archive as much as possible before beginning the migration. Obviously, this will speed up the process because there will be fewer objects to handle, but it also means that you will not be faced with correcting errors in documents from previous migrations, such as those from SAP R/2 to SAP R/3 or SAP ERP or conversions from local currencies to the euro.
Keep reading in > First Steps in SAP® S/4HANA Finance.