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Defining Information Flows

CA Gen can capture the following details for each information flow:

Name

The name of an information flow, when specified, is a free-form description of the information that is presented to or received from a process by an external object, depending on the direction of flow.

For example, the flow from customer to Take Order in the previous illustration is named "Order Details" and the one returning from Take Order to customer is named "Order Number." The name does not describe the source or destination of the flow, as that is shown by the external object.

Description

You can record any additional information deemed useful in the description.

If an information flow is optional, you record the conditions under which it is required or forbidden.

You should not record the content of the information that is passed between the external object and process. If this detail is important, you can record it as associated views.

Optionality

The optionality of an information flow indicates whether information passes between the external object and process at every execution of the process.

An open circle near the destination of the line identifies an information flow as optional in a dependency diagram.

The following illustration shows examples of four information flows associated with the process Apply For Loan.

Defining Information Flows

The flows that run between client and Apply For Loan are mandatory. For each execution of Apply For Loan, "Credit Information" must be received from a client and a "Decision" must be produced for the client.

The other two flows are optional. A "Letter of Approval" is required from a Guarantor in some cases (the optionality condition is left to the imagination of the reader), but not in others. Sometimes a loan application is passed to a Credit Rating Agency.

The conditions under which Apply For Loan requires a Letter of Approval from the Guarantor and under which Apply For Loan passes Name and Address of client to a Credit Rating Agency is documented in the description of Apply for Loan. This information also be left as part of the description of each information view until the logic of Apply for Loan is analyzed in detail.

Process logic analysis is described in the chapter "Analyzing Interactions."

Associated Views

You can specify exactly which elements of the information that is required or produced by the process pass along the information flow.

Associated views for an information flow contain attributes of many different entity types, but these entity types must correspond with the information views and expected effects of the associated process.

See the chapter "Analyzing Interactions" for a detailed discussion of associated views.