What is SAP?

ERP stands for enterprise resource planning: software that unifies the processes and data of an entire organisation. Before ERP, each department ran its own system and they were reconciled by hand. SAP’s value is integration, when a goods receipt is posted in materials management, the financial accounting entries, inventory valuation and cost postings all happen automatically and consistently. One version of the truth replaces dozens of disconnected spreadsheets and applications.

The example that makes it concrete is one that happens thousands of times a day in any large business. Somebody in a warehouse receives a delivery and confirms the quantity. In that one action the stock figure rises, the stock value rises, an accounting entry is created, the purchase order is updated with what has arrived, and the supplier's future invoice now has something to be matched against. Nobody told finance and nobody told purchasing.

That is the whole proposition, and it explains both why these systems are valuable and why they are demanding to implement. If one action updates everything, then everybody has to agree on what the action means before it can be configured.

The building block that makes it work is the document. Every business event produces one: a purchase order, a delivery, an invoice, a journal entry. Each has a number, a type and line items, and each references the documents that came before it. That chain of references is called the document flow, and it is the practical answer to almost every question anybody asks of an ERP. Why does this account have this balance, why is this stock reserved, why has this supplier not been paid: all three are answered by walking a document flow back to the event that started it.

For decades the flagship product was SAP ERP Central Component (ECC), running on traditional databases. The current generation is S/4HANA, a re-architected suite built specifically for SAP’s in-memory HANA database, with a simplified data model, real-time analytics and the modern Fiori user experience. Most new implementations and migrations today target S/4HANA, though a huge installed base of ECC systems still runs the world’s businesses.

Three differences do most of the practical work, and the rest is detail.

The database is fixed. ECC runs on several databases; S/4HANA runs on HANA and nothing else. That is what allows the rest.

The data model was simplified. Many tables that existed to hold pre-aggregated totals are gone, because HANA can aggregate on demand. Finance and controlling postings now share one journal, which removes a reconciliation that used to be a monthly task. This is also why old reports and old custom code sometimes return nothing after a conversion: they read tables that no longer hold data.

The user interface moved. Fiori is the standard interface rather than an addition, and the classic transaction screens are still there behind it.

What did not change is larger than what did. The organisational structure, the document principle, the module boundaries and the great majority of the configuration are recognisably the same, which is why consultants move between the two without retraining from scratch.

If you have access to any SAP training system, this is the shortest exercise that shows what all of the above actually means.

1. Open a purchase order that has had a goods receipt posted against it.
2. Open its history. The receipt is listed, with a material document number.
3. Open that material document. It records the logistics event: material, quantity, plant, storage location.
4. From it, follow the link to the accounting document. Two lines, in currency, that nobody typed.
5. Look at the account that was posted to. It came from the material's valuation class through a configuration table.
6. Now look at the purchase order again. The outstanding quantity has changed.

One action by one person in a warehouse, and five records in three different areas of the business are consistent with each other. Everything else you will read about SAP is machinery for making that reliable at scale.

• Finance and controlling (FI/CO), the accounting backbone.
• Procurement and materials (MM), buying and stocking goods.
• Sales and distribution (SD), quoting, ordering, delivering, billing.
• Production (PP), manufacturing planning and execution.
• HR/people (HCM, SuccessFactors), plus many industry-specific solutions.

Worth adding what SAP is not, because the name gets used loosely. SAP is a company with a large portfolio, and the ERP is one product in it. Analytics, planning, integration, human resources, procurement networks and the development platform are separate products with their own names, their own release cycles and often their own consultants. When somebody says they work in SAP, the useful follow up question is which product.

The other axis worth knowing on day one is who does the work, because it decides what you would be learning. Functional consultants configure a business area and talk to the people who use it. Technical people write and extend code and build interfaces. Basis and administration keep the systems running, patched and backed up. Analytics and integration sit alongside as their own specialisms. The three main paths need genuinely different temperaments, and most people know within a few weeks which one suits them.

SAP runs a very large share of the world’s largest companies because it is deep, integrated, industry-aware and battle-tested at massive scale. That depth is also why it takes real skill to configure and use well, which is exactly what this course builds.

The other half of the answer is switching cost, and it is not a criticism. A system that has run a business for twenty years contains twenty years of decisions, integrations, custom reports and trained staff. Replacing it means reproducing all of that, and the benefit has to be very large to justify it. This is why the market moves slowly and why experience keeps its value: the systems you learn on will still be running in a decade. See SAP careers, who uses SAP, the editions and how it evolved.

Being fair about the other side: the same properties that make it durable make it slow to change, expensive to implement and hard to like for the people who use it daily. Projects overrun, customisation accumulates, and interfaces designed decades ago are still in front of users. None of that is controversial inside the industry, and a consultant who cannot say it plainly is not much use to a client deciding what to do.

• Thinking SAP is one program, it is an integrated suite of modules on shared data.
• Confusing ECC and S/4HANA, know which generation you are working on.
• Underestimating the integration, a change in one module ripples across finance and logistics.

Version note: the naming has changed repeatedly and older material is easy to misread. R/3 became ECC, which is the generation most people mean by classic SAP; S/4HANA is the current one; and the cloud offerings have been renamed more than once. When you meet an unfamiliar name, the useful question is which generation and which deployment it refers to, because that decides whether the material still applies to what you are working on.

Understanding what SAP is takes an afternoon, and the step that turns it into work is following one full business process through a real system with somebody who can explain why each screen behaves the way it does.