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

In UML 2.2, there are 14 types of UML diagrams, categorized into two groups:

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

These diagrams can be hierarchically classified, as shown in the UML diagram below:

Question: Is UML Huge and Complex?

UML is indeed a vast topic. UML provides a large number of diagram symbols, divided into 14 distinct UML diagram types, each with different UML models designed for different purposes and addressing different aspects of development needs.

• Each of the 14 UML diagram types offers a wide range of constructs and symbols, covering various requirements across most software development projects.
• The UML specification spans over 700 pages, which is widely considered overly complex, negatively affecting perceptions and adoption of UML.
• Typically, users tend to focus on and use only a portion of the UML diagrams and constructs.

Answer: Learn the Basic UML Diagrams and Symbols

Grady Booch, one of the principal creators of UML, stated, “For 80% of all software, you only need 20% of UML.”

What Does the UML Survey Say?

If a diagram is considered “rare,” we can interpret the UML survey results based on assumptions:

• Widely used if ≥60% of sources report it
• Almost unused if ≤40% of sources report it

Creating a UML Learning Plan

Based on the data collected from the survey, you can create a meaningful UML learning plan to better understand how to start your UML journey. This article also provides an image map that allows quick access to a series of “What is a UML Diagram?” guides (just click on the UML diagram box in the image map above). Enjoy!

Learn UML. Draw UML.

Get Visual Paradigm Community Edition, a free UML tool that helps you learn UML faster and more effectively. Visual Paradigm Community Edition supports all 14 UML diagram types. Its award-winning UML modeler is easy to use and intuitive.

Related Links

1. UML Class Diagram Tutorial
   • Visual Paradigm. (2022, September 2). UML Class Diagram Tutorial.
2. What does an “a” mean in Class diagrams?
   • Stack Overflow. (2017, July 28). What does an “a” mean in Class diagrams?.
3. Lab: Creating Class Diagrams in Visual Paradigm
   • James Madison University. (n.d.). Lab: Creating Class Diagrams in Visual Paradigm.
4. Class Diagram Tutorial | UML Modeling with Visual Paradigm
   • UML. (n.d.). Class Diagram Tutorial | UML Modeling with Visual Paradigm.
5. Online Class Diagram Software
   • Visual Paradigm Online. (n.d.). Online Class Diagram Software.
6. Visual Paradigm Class Diagram Drawing
   • Stack Overflow. (2013, February 10). Visual Paradigm Class Diagram Drawing.
7. Class Diagram Templates
   • Visual Paradigm Online. (n.d.). Class Diagram Templates.
8. Free Class Diagram Tool
   • Visual Paradigm Online. (2019, June 6). Free Class Diagram Tool.
9. Class Diagram Tutorial
   • Visual Paradigm Online. (2010, January 11). Class Diagram Tutorial.
10. What is Class Diagram?
    • Visual Paradigm. (2022, February 9). What is Class Diagram?.

*Reference – What UML Diagrams Are Used? A Preliminary Survey, Gianna Reggio, Maurizio Leotta, Filippo Ricca, Diego Clerissi DIBRIS – University of Genoa, Italy