In a static structure diagram, an n-ary association is an association among three or more classes (a single class can appear more than once). Each instance of the association is an ordered set of values from the respective classes. No association end in an n-ary association can contain the aggregation marker. An n-ary association can be an association class with attributes, operations, and other properties.
Name an N-ary Association shape and add adornments to its ends
Open the element's UML Properties dialog box by double-clicking the icon that represents the element in the tree view or the shape that represents the element in a diagram.
Control which property values display on a shape in a diagram by right-clicking the shape, and then clicking Shape Display Options. In the UML Shape Display Options dialog box, select and clear options to display or hide property values.
Choose the number of n-ary association ends
Double-click the N-ary Association shape, and then, for End Count, choose the number of ends you want.
Control which property values are displayed on the N-ary Association shape
Right-click the shape, click Shape Display Options, and then select or clear options to show or hide values.
Navigate to other views of the n-ary association
Right-click the shape, click Views, select the view you want, and then click OK.