How the Collector Locates the Components that are Associated with a Composite Object
To identify the components of a composite object, the collector finds objects that are related to the composite object by an aggregation relationship or a reverse-aggregation relationship.
An aggregation relationship is indicated by the presence of an
aggregated Relationship attribute in the composite object. Like a regular Relationship attribute, an aggregated Relationship attribute associates an asset with other objects in the registry. However, an aggregated Relationship attribute additionally indicates that the associated objects are components of the object that contains the aggregated Relationship attribute.
A reverse-aggregation relationship is indicated by a
reverse-aggregated Relationship attribute that is present in another registry object and points back to the object on which the collection is being performed. Like a regular Relationship attribute, a reverse-aggregated Relationship attribute also associates an asset with other objects in the registry. However, a reverse-aggregated Relationship attribute additionally indicates that the object that contains the reverse-aggregated attribute is a component of the object at the end of the relationship.
Conceptually, both the aggregated and reverse-aggregated forms of the Relationship attribute establish a parent-child relationship between the object being collected (the parent) and objects that are its components (its children). However, the aggregated form expresses the relationship from the perspective of the parent object (that is, the aggregated Relationship attribute exists in the composite object and identifies the object's components), whereas, the reverse-aggregated form expresses the relationship from the perspective of a child object (that is, the reverse-aggregated Relationship attribute exists in a component object and identifies the composite object to which it belongs). The components that make up a composite object can be identified using aggregated Relationship attributes, reverse-aggregated Relationship attributes or a combination of the two.
Aggregated Relationship attributes are specified during the type definition for a composite object. Reverse-aggregated Relationship attributes are specified during the type definition of a component object.
