Code Diagram (Level 4)
Zooms into a single component showing its internal structure
at the code level (classes, interfaces, modules). Typically auto-generated
from source code. Answers: "How is this component implemented?"
Purpose: Designing
Concerns: StructureConcern
View type: Diagram
Component Diagram (Level 3)
Zooms into a single container showing its internal components
and their relationships. Answers: "What are the major structural
building blocks inside this container?"
Purpose: Designing
Concerns: StructureConcern, DependencyConcern
View type: Diagram
Container Diagram (Level 2)
Zooms into a single software system showing its containers
(applications, services, databases) and their interactions. Answers:
"What are the major technical building blocks and how do they communicate?"
Purpose: Designing, Informing
Concerns: StructureConcern, IntegrationConcern
View type: Diagram
System Context Diagram (Level 1)
The highest abstraction level. Shows the software system in
scope and its relationships with users and other systems. Answers:
"What is the system and who uses it?"
Purpose: Informing
Concerns: StructureConcern, StakeholderConcern
View type: Diagram
System Landscape Diagram
Shows all software systems and people across the enterprise,
not just a single system in scope. A "zoomed out" version of the
System Context diagram.
Purpose: Informing
Concerns: StructureConcern, DependencyConcern
View type: Diagram