Fundamentals of UML Diagrams

A diagram is the graphical presentation of a set of elements. UML has a lot of different diagrams. Make sure you can differentiate between different diagrams. Previous sections described UML diagrams; this section elaborates on them using examples.

Basic Use Case Notation

A diagram is the graphical presentation of a set of elements, most often rendered as a connected graph of vertices (things) and arcs (relationships). You draw diagrams to visualize a system from  different perspectives, so a diagram is a projection into a system. UML has a lot of different diagrams (models). The reason for this is that it is possible to look at a system from different  viewpoints. UML being a graphical language includes nine such diagrams models):

  1. Class diagram
  2. Object diagram
  3. Use case diagram
  4. Sequence diagram
  5. Collaboration diagram
  6. Statechart diagram
  7. Activity diagram
  8. Component diagram
  9. Deployment diagram

UML nine diagrams can be divided into two categories

(a) Four diagram types represent static application structure:

  • Class Diagram
  • Object Diagram
  • Component Diagram
  • Deployment Diagram

(b) Five represent different aspects of dynamic behaviour

  • Use Case Diagram
  • Sequence Diagram
  • Activity Diagram
  • Collaboration Diagram
  • Statechart Diagram

Source: Adapted from Ellen Ambakisye Kalinga
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