Properties of attributes on UML class diagrams
Note
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On a UML class diagram, you can add attributes to classes and interfaces. An attribute defines values that can be attached to instances of the class or interface.
To add an attribute, right-click the class or interface, point to Add, and then click Attribute.
If the attributes of a class on the diagram are not visible, click the chevron at the top of the class or interface to expand it. If you can see the Attributes header, click [+] to expand the attributes section.
Signature of an Attribute
An attribute's signature is the line that represents it in a class or interface on a UML class diagram. It has this form:
+ AttributeName : TypeName [*]
+ denotes public Visibility. The other permitted values are - (private), # (protected), ~ (package).
AttributeName is underlined if the attribute is static.
: TypeName is omitted if the attribute has no type.
[*] denotes the multiplicity. It is omitted if the multiplicity is 1.
Properties
The following table describes the properties of an attribute in a class or interface on a UML class diagram.
To see the properties of an attribute, right-click the attribute in the class or interface on the diagram, and then click Properties. The properties appear in the Properties window.
To view the properties of an attribute, right-click it and then click Properties.
| Property | Default | Description |
|---|---|---|
| Default Value | (empty) | The value of the attribute when the classifier is instantiated. |
| Is Read Only | False | If true, the value of the attribute cannot be changed. |
| Is Static | False | If true, a single value for this attribute is shared between all instances of this type. If true, the name of the attribute is underlined where it appears on the diagram. |
| Name | (a new name) | Should be unique within the owning classifier. |
| Type | (none) | A primitive type such as Integer, or a type that is defined in the model. You cannot use non-primitive types such as Decimal because the value must be encoded in the metadata. If you enter a name for a new type in this property, a type will be added to the Unspecified Types section of UML Model Explorer. |
| Visibility | Public | The permitted values, and the characters that appear in the signature are as follows: + Public - visible globally - Private - not visible outside the owning type # Protected - visible to types derived from the owner ~ Package - visible to other types within the same package. |
| Work Items | 0 associated | Count of associated work items. Read-only. For more information, see Link model elements and work items. |
| Is Leaf | False | If true, it is not intended to allow redefinition of this attribute in derived types. |
| Is Derived | False | If true, this attribute is calculated from other attributes. For example, Diagonal, calculated from Width and Height. The details should be written in the Description or an attached Comment. |
| Description | (empty) | For general notes, or for defining constraints on the values in the attribute. |
| Multiplicity | 1 | 1 - this attribute has a single value of the specified Type. 0..1 - this attribute can have a value of null.\* - this attribute's value is a collection of values. 1..\* - this attribute's value is a collection that contains at least one value. n .. m - this attribute's value is a collection that contains between n and m values. |
| Is Ordered | False | If true, the collection forms a sequential list. For Multiplicity of more than 1. |
| Is Unique | False | If true, there are no duplicate values in the collection. For Multiplicity of more than 1. |
See Also
UML Class Diagrams: Reference Properties of types on UML class diagrams Properties of operations on UML class diagrams UML Class Diagrams: Guidelines UML Class Diagrams: Guidelines