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Defining External Objects

Sometimes a process executes when it receives information from an external source. For example, Take Order executes when an order is received from a customer.

CA Gen allows you to define types of objects from which a process can receive information and to which a process send information. Such objects are called external objects and are depicted on the Process Dependency Diagram as two stacked red boxes. See customer in the following illustration.

Defining External Objects

The interaction of an external object with a process is shown as a directed line connecting the two. This line is not confused with a dependency; rather, it indicates an information flow.

In CA Gen Activity Dependency Diagrams, information flows are colored cyan (light blue) to distinguish them from dependencies (white).

The illustration depicts the fact that a customer sends the order details that are required by the Take Order process and receives order number information that is produced by the Take Order process.

You can use an external object to show virtually any source of information that is required by a process, or the destination of information that is produced by the process.

In most cases, external objects are considered to be outside the analysis model in which the process appears; hence, the designation "external."

Sometimes they imply business activities or systems external to the analysis model.

Sometimes they are given the name of an entity type that is represented in the associated information flow.

Occasionally a specific entity, such as a bank or government agency, is included as an external object.

Give each external object a short textual name, and optionally, a short description. There are no explicit rules naming external objects. Where the name of a business activity is known, use this name. It is not unusual for an external object to have the same name as an entity type. This does not mean that external objects can represent data stores, or that attributes in an associated information flow are restricted to belonging to one specific entity type.

CA Gen does not enforce a rigorous definition of external objects. When changing the name of an activity or entity type represented also an external object, also change the name of the external object.