Migrating from SAP ECC to S/4HANA is not a simple "upgrade" operation. In this process — where both the database (HANA) and the application logic change — your existing custom ("Z") code must go through a detailed analysis and be adapted accordingly.
Simplification List
SAP publishes a hundreds-of-pages "Simplification List" with each new S/4HANA release. This list details which functions have changed and which have been removed. Before starting the project, the points where your system's custom code conflicts with this list must be analysed using the SAP Readiness Check and Custom Code Migration App.
Custom Code Adaptation Process
1. Scoping & Analysis
Identifying unused code (Dead Code). Programs with a "Z" prefix that have not executed in the past year are identified using SCMON (ABAP Call Monitor) and excluded from the migration scope.
2. ATC (ABAP Test Cockpit) Checks
All code is scanned using the S/4HANA readiness check variant. Critical errors (Syntax Errors) and performance warnings (e.g. SELECT SINGLE without ORDER BY) are reported.
3. Remediation
Correcting faulty code. Quick Fix features in Eclipse allow bulk corrections to be applied efficiently.
Critical Changes in the Data Model
With S/4HANA, aggregate tables have been removed to improve performance and the "Universal Journal" structure has been introduced.
- ACDOCA (Universal Journal): On the accounting side, many tables such as BSIS, BSAS and FAGLFLEXA have been replaced by a single "ACDOCA" table. Although the old tables continue to exist as Compatibility Views, new reports should be written directly against ACDOCA for performance.
- MATDOC (Material Document): On the logistics side, the MKPF (header) and MSEG (item) tables have been replaced by the MATDOC table. This table enables much faster querying of material movements.
Conclusion
A successful S/4HANA project is not just a technical transformation — it is also an opportunity to improve your code quality. Önder Yazılım provides end-to-end technical consulting services for migration projects.
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