UML Class Diagram Tutorial | What is Class Diagram?
What is a Class Diagram?
The UML Class diagram is a graphical notation used to construct and visualize object-oriented systems. A class diagram in the Unified Modeling Language (UML) is a type of static structure diagram that describes the structure of a system by showing the system’s:
- classes,
- their attributes,
- operations (or methods),
- and the relationships among objects.
What is a Class?
A Class is a blueprint for an object. Objects and classes go hand in hand. We can’t talk about one without talking about the other. And the entire point of Object-Oriented Design is not about objects, it’s about classes, because we use classes to create objects. So a class describes what an object will be, but it isn’t the object itself.
UML Class Notation
A class represent a concept which encapsulates state (attributes) and behavior (operations). Each attribute has a type. Each operation has a signature. The class name is the only mandatory information.
Relationships between classes
In class diagrams, relationships between classes describe how classes are connected or interact with each other within a system. There are several types of relationships in object-oriented modeling, each serving a specific purpose. Here are some common types of relationships in class diagrams:
