Visual SAP with plantUML #7 C4 Model

C4 stands for:

1. Context – Where the system sits in the bigger world

2. Container – What it consists of (apps, DBs, APIs)

3. Component – What’s inside each container

4. (Code — optional)

It’s not UML, but a practical way to show how a system works — at different levels of zoom.

---

📌 Why Use C4 in SAP Projects?

---

🧠 Levels You Actually Need

In most SAP projects, you’ll mostly use:

• Level 1 — Context (systems + people)

• Level 2 — Container (apps, APIs, DBs)

That’s enough for 90% of real-world needs.

---

✍️ Notation in PlantUML (C4 Library)

You need to import the C4 library:

plantuml
CopyEdit
!includeurl <https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Context.puml>

Use:

• Person()

• System()

• System_Ext()

• Container()

---

✅ C4 Level 1 — Context Diagram (SAP Integration)

pl
CopyEdit
@startuml
!includeurl <https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Context.puml>

Person(user, "Sales Rep")
System(s4hana, "SAP S/4HANA")
System_Ext(crm, "External CRM")
System_Ext(po, "SAP Process Orchestration")

user --> s4hana : uses Fiori apps
s4hana --> po : sends IDocs
po --> crm : sends formatted data

@enduml

This answers:

"Where is SAP in the bigger system landscape?"

---

✅ C4 Level 2 — Container Diagram (S/4HANA View)

plantuml
CopyEdit
@startuml
!includeurl <https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Container.puml>

System_Boundary(s4, "SAP S/4HANA") {
  Container(fiori, "Fiori Launchpad", "UI5", "User interface for business processes")
  Container(gateway, "SAP Gateway", "OData/RFC", "Exposes backend logic")
  Container(appcore, "Application Layer", "ABAP", "Implements core logic")
  Container(db, "HANA DB", "HANA", "Stores transactional data")
}

Person(user, "Internal User")
user --> fiori
fiori --> gateway
gateway --> appcore
appcore --> db

@enduml

This answers:

"What’s inside SAP, and how do the parts work together?"

---

✅ When to Use C4 in SAP

---

🧠 Pro Tips

✅ Use System_Ext for non-SAP systems

✅ Add short descriptions for clarity

✅ Use it in workshops, proposals, architecture decks

✅ Keep C4 Level 1 + 2 separate — different audiences

---

✅ Summary

C4 helps you think in layers:

“What’s outside?” → “What’s inside?” → “How does it run?”

It’s the fastest way to communicate SAP architecture without confusion.

Use it to:

• Show integrations

• Document system structure

• Align across tech & business