SAP & S/4HANA basics

An ERP (enterprise resource planning) system runs a company’s core processes on one shared database: buying, making, storing, selling and accounting. When a warehouse worker posts a goods receipt, stock goes up and the accounting entry is made at the same moment, because it’s one system. SAP is the most widely used ERP among large companies.

SAP is organized into modules that match business areas:

Every transaction is tied to an organizational structure: a company code (the legal entity), plants (factories or sites), storage locations, a purchasing organization, and sales areas. Master data, such as the material master, the Business Partner record for customers and suppliers, and prices, is set up once and reused by every transaction.

S/4HANA is SAP’s current generation, replacing the older ECC. It runs only on the in-memory HANA database, simplifies the data model (one material document table, MATDOC, and the Universal Journal, ACDOCA, for all financial postings), makes Business Partner the single record for customers and suppliers, and offers Fiori apps alongside the classic transaction codes (T-codes) such as ME21N or VA01.

Organizational levels

Every transaction is posted against these levels. A purchase order belongs to a purchasing organization and delivers to a plant and storage location; a sales order belongs to a sales area and ships from a shipping point. If a level is missing or wrongly assigned, transactions fail.

Master data is organized by the same levels

The material master is split into views, each maintained at a different level:

• Basic data: description, unit of measure, weight. Same for the whole client.
• Purchasing, MRP, work scheduling, storage: per plant (MRP type, lot size, lead times, purchasing group).
• Accounting and costing: per valuation area, usually the plant (price control, price, valuation class).
• Sales: per sales organization and distribution channel (delivering plant, item category group).

That is why a material can exist and still be unusable in a particular plant or sales area: the views for that level haven’t been created. The Business Partner works the same way, with roles for customer and supplier and data per company code, purchasing organization or sales area.

Three kinds of data

• Configuration (customizing): the system’s rules, set up in the implementation guide (transaction SPRO), such as document types, account determination and tolerance limits. Changed rarely, by consultants or key users.
• Master data: long-lived records such as materials, business partners, prices, bills of materials and routings.
• Transactional data: the documents created every day: orders, deliveries, goods movements, invoices.

Every business event creates a numbered document (a purchase order, a material document, an accounting document), and documents link to each other, which is how SAP builds an audit trail from order to payment.

What S/4HANA changed under the hood

• In-memory, columnar database: HANA keeps data in memory, so reports and planning runs read live transactional data instead of separate aggregate tables.
• Simplified tables: goods movements land in MATDOC instead of the older header and item tables (MKPF and MSEG), and financial and controlling postings meet in the Universal Journal, ACDOCA.
• Business Partner replaces separate customer and vendor masters, synchronized through customer-vendor integration.
• Material ledger is always active for inventory valuation, supporting parallel currencies.
• Fiori apps provide role-based screens and embedded analytics, alongside classic transactions.
• New engines: MRP Live for faster planning, advanced ATP for order promising, embedded EWM and PP/DS.

The end of ECC

SAP’s mainstream maintenance for ECC 6.0 runs to the end of 2027, with optional extended maintenance to 2030. That deadline drives a wave of S/4HANA projects, and with them demand for people who understand both the business processes and the new system.

Getting there: three approaches

• Greenfield (new implementation): design processes afresh on S/4HANA and migrate only master data and open items. Most change, most opportunity to simplify.
• Brownfield (system conversion): convert the existing ECC system, keeping history and customizations. Faster, but carries old complexity forward.
• Selective data transition: a middle path, moving chosen data and processes into a new system.

Clean core

SAP’s guidance is to keep the core system close to standard and build extensions outside it, on its Business Technology Platform, using released interfaces. Heavy modifications make upgrades expensive and slow; a clean core makes it easier to adopt new releases.

How SAP projects run

Projects typically follow SAP Activate: discover, prepare, explore, realize, deploy and run. In fit-to-standard workshops, the team shows standard processes to the business and records only the gaps that truly need something different. Roles include functional consultants for each area (MM, SD, PP, FI/CO, EWM), technical developers, Basis administrators, and key users from the business who test, train colleagues and own processes after go-live.