An Activity Diagram shows a step-by-step process:

what happens, in what order, and with what conditions or decisions.

In SAP terms, think of:

Creating a sales order
Posting goods issue
Running a workflow approval
Processing a delivery or invoice

It helps you visualize logic, align dev & functional teams, and clarify edge cases.

📌 When to Use Activity Diagrams

Use Case	Why It Helps
Describing functional processes	Clear step-by-step overview
Communicating logic to developers	Avoids misunderstanding
Preparing for enhancements	Clarifies where to insert logic
Documenting decisions / branches	Shows conditions and outcomes clearly

🧩 Activity Diagram Notation (PlantUML)

Element	Syntax	Meaning
Start	`start`	Entry point
Action step	`:Some action;`	A single step in the process
Decision	`if (...) then (...) else (...)`	Conditional logic
Parallel (opt.)	`fork`, `end fork`	Parallel execution
End	`stop`	End of process

You read it top to bottom — like a flowchart.

✅ Example: Goods Issue Process

pl
CopyEdit
@startuml
title Activity Diagram — Goods Issue Flow

start

:Create Outbound Delivery;
:Check Stock Availability;

if (Stock available?) then (yes)
  :Pick and Pack;
  :Post Goods Issue;
else (no)
  :Trigger Exception Handling;
endif

:Send Confirmation;

stop
@enduml

This is readable. You can explain it to:

Functional team
Developer
Business stakeholder

All without opening SAP.

⚙️ Rules to Remember

Each step = :Action;
One decision = if (...) then (...) else (...)
Always start with start, end with stop
Keep it functional, not technical
Use verbs: "Post", "Check", "Create", "Send"

🧠 Pro Tips

✅ Use simple wording

✅ Avoid clutter — 5–9 steps per diagram is ideal

✅ For long processes — split into separate diagrams

✅ Reuse in specs, training, onboarding

🔧 Minimal Example for Custom Logic

plantuml
CopyEdit
@startuml
title Activity Diagram — Approval Workflow

start

:User submits request;
:Trigger Workflow;
:Check Approver Role;

if (Is Manager?) then (yes)
  :Auto-approve;
else (no)
  :Send to Manual Approval;
endif

:Update Status;
:Notify User;

stop
@enduml

This could be MM, SD, HR — doesn’t matter.

The pattern is universal.

✅ Summary

Activity diagrams make logic visible.

If you're designing or changing a business process — this is how you explain it.

Use them to:

Describe flows
Show decisions
Align teams

They save time, avoid confusion, and clarify intent.

Next up:

👉 Visual SAP #4 — Sequence Diagrams That Show How SAP Systems Talk

We’ll cover integration flows: IDocs, APIs, RFCs — and how to show “who calls whom, when, and with what.”

Visual SAP with plantUML #3: Activity Diagram — Think in Flows