Model Parts, Diagrams, Dictionary Items, and Properties > Properties > Aggregation (property)
  
Aggregation (property)
For automation interface information about the Aggregation property (Aggregate through the automation interface), see the automation interface topic for an Association in the Related Topics.
This property specifies that an Association represents an aggregation relationship between two items, that is, Classes, Data Types, Interfaces or Signals. An Association represents an aggregation when 'part of' or 'made up of' is selected from the following list box on the Start Role or End Role tab of an Association's Property Pages.
On a Class Diagram, an Aggregation is indicated through a diamond symbol.
By default, if you add an Association through the Composite Aggregation toolbar button, 'made up of' is selected on the Start Role tab, and 'part of' is selected on the End Role tab.
This property is set on the Start Role and End Role tabs of an Association's Property Pages.
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If you select the UML\Associations folder in the Dictionary pane, the Contents pane shows the Aggregation of each Association in the model. The Aggregation can be None, Start or End, where None means that the Association is not used to model an Aggregation.
The following section provides information about the items and diagrams for which Aggregation is a property. For more information about an item or diagram, click it.
Is property of
Association