The class diagram. A structured path towards systems.


What is a class diagram?

Class diagrams describe systems by  illustrating attributes, operations and relationships between classes. Unified Modeling Language (UML) calls them structure diagrams. They work according to the principles of object orientation. This orientation describes how objects interact with each other.

Class is a term for the collective structure and the combined behavior of objects (classification). In other words: objects are included in a class if they have similar properties – i.e. the mutual properties in specific objects are grouped into a single class.

What is a class diagrams used for?

Class diagrams give you the ability to create models with the help of UML using attributes, relationships, operations and intersections. A class diagram visualizes the paths between classes in the form of aggregations and associations as well as through the passing on of properties and behavior between classes. These take the form of generalizations.

Class diagrams are the most important kind of UML diagram and are vitally important in software development. Class diagrams are the best way to illustrate a system’s structure in a detailed way, showing its attributes, operations as well as its inter-relationships. Classes play a significant role in object orientated programming languages – they are indispensable when it comes to software modelling.

Why is the class diagram so important?

Class diagrams are at the heart of UML. They are based on the principles of object orientation and can be implemented in various phases of a project. During the analysis they appear as the domain model where they attempt to create a representation of reality. During the design phase the software is used to model software, and during the implementation phase it can be applied to generate source code. Class diagrams are a vital part of any software development project and they form the foundation of all software products.