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Overview of the 14 UML Diagram Types

The Unified Modeling Language is a standardized general-purpose modeling language and nowadays is managed as a de facto industry standard by the Object Management Group (OMG). UML includes a set of graphic notation techniques to create visual models for software-intensive systems.

In UML 2.2 there are 14 types of UML diagrams, which are divided into two categories:

  • 7 diagram types represent structural information
  • Another 7 represent general UML diagram types for behavioral modeling, including four that represent different aspects of interactions.

These diagrams can be categorized hierarchically as shown in the following UML diagram map:

Timing Diagram Interaction Overview Diagram Communication Diagram Sequence Diagram State Machine Diagram Use Case Diagram Activity Diagram Component Diagram Object Diagram Class Diagram Profile Diagram Package Diagram Deployment Diagram Composite Structure Diagram

(You may click on individual UML diagram above to open the corresponding UML diagram guide)

Question: UML is Huge and Complex?

UML is a truly a huge topic. UML provides a large volume of diagramming notation grouped into 14 different UML diagram types, each with different UML models, serving different purposes and addressing different aspects of development needs.

  • Each UML diagram of the 14 UML diagram types provides a large set of constructs and notation that cover different needs for most of the software development projects.
  • UML specification has more than 700 pages, and clearly considered as too complex and has a negative impact on the perception and adoption of UML.
  • Typically, users tend to consider and use only a portion of its diagrams/constructs of UML.

Answer: Learn the Most Essential UML Diagrams and Notation

Grady Booch, one of the most important developer of Unified Modeling Language, stated that "For 80% of all software only 20% of UML is needed".

What is the UML Survey* States?

We could interpret the results of the UML survey by assuming that, if a diagram is

  • widely used, if it ≥ 60% of the sources
  • scarcely used if it is ≤ 40% of the sources
Activity Diagram Example - Word Processor

Make Your UML Learning Plan

Based on the figures collected in the survey, you can have a better idea on how to start your UML learning journey by developing a meaningful UML learning plan. This article also provides you with an image map for quickly visiting to a series of "What is UML Diagram"papers (Just click the boxes of UML diagram in the image map above). Enjoy!

* Reference - What are the used UML diagrams? A Preliminary Survey, Gianna Reggio, Maurizio Leotta, Filippo Ricca, Diego Clerissi DIBRIS - Universit'a di Genova, Italy

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