The characteristics that shape every migration off this platform.
MANDT — client partitioningAlmost every application table is client-dependent with the client as the leading key. An extract that does not constrain it blends production with test and training data into a set that reconciles perfectly against itself and is still wrong.
BKPF / BSEG — header and lineFinancial documents split across a header and its line items. A complete posting means joining them and preserving the document key, and BSEG is a cluster-style structure rather than a simple transparent table, which constrains how it can be read.
KNA1 / LFA1 / MARA — master data familiesCustomer, vendor and material general views head wider families of company-code and organisational-level tables. A usable master record is always an assembly, never one row.
Check tables and domain valuesSAP validates codes against check tables and domain fixed values rather than storing labels. Reference and text tables are extracted alongside the transactions or the result is uninterpretable once ECC is off.
Internal number rangesMany keys are assigned internally and mean nothing outside SAP. The migration decides per object whether the legacy key travels as a cross-reference or is dropped for a target-generated key.
BUKRS / KOSTL / HKONTCompany code, cost centre and G/L account carry the organisational meaning of every posting, and must line up with the target's enterprise structure before transactional data can land.