Visual SAP with plantUML #8 Diagram Toolkit — When to Use What and Why
Dzmitryi KharlanauThere are many diagram types — but not all are useful all the time.
This guide gives you:
A decision table: pick the right diagram for your goal
A reference sheet: syntax + use cases
A mental map to avoid analysis paralysis
🧭 Diagram Decision Table
| Your Goal | Use This Diagram | Why |
| Show tables, relationships, keys | ER Diagram | Clarifies data structure, joins, master data |
| Explain architecture & modules | Component Diagram | Shows what talks to what, system-level logic |
| Describe step-by-step process logic | Activity Diagram | Visualizes flow, decisions, and outcomes |
| Map interface flow across systems | Sequence Diagram | Clarifies who calls whom and when |
| Model ABAP logic, classes, interfaces | Class Diagram | Clean object structure for custom code |
| Show who does what (roles & functions) | Use Case Diagram | High-level overview of responsibilities |
| Explain full system architecture | C4 Model (Context) | Landscape and system-to-system interaction |
| Break down internal structure of SAP | C4 Model (Container) | What’s inside: apps, APIs, DBs |
| Describe business workflow for approval | BPMN | Business-readable process with decisions and triggers |
📘 Reference Sheet — SAP Diagram Syntax (PlantUML Style)
| Diagram | Key Syntax Elements | Note |
| ER | entity, ` | |
| Component | component, package, --> | System/module interaction |
| Activity | start, :Action;, if () then | Step-by-step logic |
| Sequence | participant, ->>, --> | Interface/integration timing |
| Class | class, + method(), `.. | \>, *--` |
| Use Case | actor, usecase, --> | Roles and their actions |
| C4 | System(), Container(), Person() | Requires C4-PlantUML include |
| BPMN (external) | Use in draw.io, bpmn.io, Camunda Modeler | Not native to PlantUML |
🛠 How to Think When Choosing a Diagram
Ask:
Am I describing data, flow, or structure?
Who is this for — business, devs, integration team?
What level of detail matters — logic, or big picture?
Use diagrams that:
Clarify, not overwhelm
Serve 1 purpose per diagram
Can be reused or versioned (hint: PlantUML = .txt)
🎯 Example Scenarios
| Scenario | Diagram Type |
| Designing Z-table with links | ER Diagram |
| Building a custom RFC + app flow | Component + Sequence |
| Explaining PO-to-GR logic to devs | Activity Diagram |
| Showing who approves what in workflow | Use Case + BPMN |
| Mapping BTP extension with on-prem backend | C4 Context + Container |
✅ Summary
The goal is not “use diagrams.”
The goal is think better, communicate faster, and avoid rework.
This toolkit helps you:
Choose the right diagram
Use the right syntax
Apply it in real SAP projects
No more guessing. Just pick, write, explain, deliver.
Subscribe to my newsletter
Read articles from Dzmitryi Kharlanau directly inside your inbox. Subscribe to the newsletter, and don't miss out.
Written by
Dzmitryi Kharlanau
Dzmitryi Kharlanau
SAP Logistics Consultant with 10+ years of experience in SAP SD, SAP MM, SAP LE, and SAP IS-Automotive. Skilled in SAP system support, integration, and process improvements. Achievements ✔️ Delivered custom logistics solutions, overseeing the entire process from concept to go-live. ✔️ Achieved SLA compliance in JIT environments, managing tasks from requirements to release independently. ✔️ Resolved complex issues swiftly, minimizing downtime and optimizing efficiency. Interests: Motivated to work with 🔧 S/4HANA SD, MM, BTP, and ABAP, taking responsibility for end-to-end solutions.