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Software Architecture Guide

UML 2.5 Diagram Taxonomy

Explanation

Section titled “Explanation”

UML has 14 diagram types, and UML 2.5 keeps that set unchanged. The types are arranged in a taxonomy: a family tree that sorts diagrams into groups.

Two main groups

  • Structure diagrams show the static view of a system. They describe how it is built, so they document its architecture. The profile diagram sits in this group.
  • Behavior diagrams show the dynamic, runtime view. They describe what the system does and how its parts work together.

A subgroup inside behavior

Interaction diagrams are a subset of behavior diagrams. They stress the flow of control and data.

Why the taxonomy helps

Each diagram type answers a different kind of question. Sorting them into structure and behavior helps you pick the right one. Ask first whether you need to show what the system is made of or what it does. Then choose a type from that group.

For more on each group, see the articles “UML Structure Diagram” and “UML Behavioral Diagram”.

Example

Section titled “Example”

A team documents an online shop. To show which parts exist, they draw a structure diagram. To show how an order request moves between those parts, they draw an interaction diagram. Interaction diagrams belong to the behavior group, so the two questions map to the two main groups.

Trade-offs

Section titled “Trade-offs”

The two-way split is broad. It helps you choose a group, but it does not tell you which of the 14 types fits a given question. The verified facts here do not describe each type in detail.

Simplified view of the UML taxonomy: structure and behavior, with interaction as a subgroup of behavior.

Diagram source 
graph TD
  D[UML diagrams: 14 types] --> S[Structure diagrams]
  D --> B[Behavior diagrams]
  B --> I[Interaction diagrams]

Checks

Section titled “Checks”
  • Each diagram in the architecture document is identified as a structure diagram or a behavior diagram.
  • Diagrams that show the static architecture are structure diagrams.
  • Diagrams that show flow of control and data are treated as interaction diagrams, a subset of behavior diagrams.
Section titled “Related”

Sources

Section titled “Sources”