Defining associations

Visibility

The visibility of an association refers to the way in which it can be seen by other objects. An association that is visible to another object may influence the structure or behavior of the object, or similarly, its own properties may be affected by the other object.

Property

Private

Protected

Package

Public

Visible

Only to the association itself

Only to the association and its inherited objects

To all objects contained within the same package

To all objects

Aggregation/composition of an Association

You can define one of the roles of an association as being either an aggregation or a composition in the Aggregation/composition group box.

Property

Aggregation

Composition

Container

Indicator

Description

An form of association that specifies the relationship between two classes of the same level

A form of aggregation of an association in which the class attached to the association role may be a part of only one composite at a time

Specifies which of the two roles is an aggregation or a composition

Indicates that the association is an aggregation or a composition

Changing an association into an associative class

You can transform an association into an associative class linked by two associations. Next, you can attach class attributes to this associative class, that you could not attach to the association.

The associative class gets the name and code of the association. You can define cardinality properties for each of the two associations created between the new class and the two existing classes.

ϖTo change an association into an associative class:

1 Right-click an association.

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Sybase 7.5 manual Changing an association into an associative class, Aggregation/composition of an Association, 102