> For the complete documentation index, see [llms.txt](https://dotnetweb30-ke.gitbook.io/ke/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dotnetweb30-ke.gitbook.io/ke/design/modeling/uml-class-diagram-essentials.md).

# UML: Class Diagram (Essentials)

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A **class diagram** describes the types of objects in the system and the various kinds of static relationships that exist among them. Class diagrams also show the properties and operations of a class and the constraints that apply to the way objects are connected.
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The UML uses the term feature as a general term that covers properties and operations of a class.

The boxes in the diagram are classes, which are divided into three compartments: the name of the class (in bold), its attributes, and its operations. also shows two kinds of relationships between classes: associations and generalizations.

More specifically, each class has 3 fields: the class name at the top, the class attributes right below the name, the class operations/behaviors at the bottom.

![](/files/-LjCa2cQDFIOM39Iszqi)

**Properties**: represent structural features of a class. As a first approximation, you can think of properties as corresponding to fields in a class.

**Attributes**: the attribute notation describes a property as a line of text within the class box itself.

![](/files/-LjCaxH0FBXiksPcrKLf)

**Associations**: much of the same information that you can show on an attribute appears on an association. This is the same properties represented in the two different notations.

![](/files/-LjCb3heU4kz1DYgr2Je)