Procedure Step Execution

Designing the Procedure Dialog › Procedure Step Execution

Procedure Step Execution

To understand building dialog flows between procedures, you need to know the relationship between procedure steps, Procedure Action Diagrams, displays, and dialog flows. Each makes its own contribution to implementing a business system.

Dialog flows provide the means by which one procedure step, based on the results of its execution, can pass control and data to another procedure step.
A procedure step, whether online or batch, controls the use of Procedure Action Diagrams.
An online procedure step also controls the use of displays.
A source procedure step can stop executing at any point in its logic, and so initiate a flow or a display.
A destination procedure step can execute only from the beginning of its logic; in other terms, a flow is always to the beginning of a procedure step.

The following illustration describes how a display, Procedure Action Diagram, and dialog flow work together during the execution of an online procedure step in the CA Gen environment.

Displaying Procedure Action Diagram and Dialog Flow together

For an explanation of the components of this illustration, see the following table.

Key	Description
1	Procedure step execution usually begins when a user enters data on a display and presses either the Enter key or a function key.
2	The data captured on the display is mapped into the import data view for the procedure step. The chapter “Designing Screens” discusses the connection between fields on the display and a procedure step's data views.
3	The import data view, whether from a display or another procedure step, is processed by the Procedure Action Diagram that supports the procedure step being executed. At its conclusion, the procedure step populates its export data view. For information about procedures, see the chapter “Designing the Procedure Logic.”
4	Based on a condition set by the Procedure Action Diagram, the procedure step either shows a display or flows to another procedure step. Such a condition, called an exit state, is described in How Flows Are Initiated.
5	If the decision in key 4 is to show a display, the data from the procedure step's export data view is mapped into the associated display and the display is shown again.
6	If the decision in key 4 is to flow to another procedure step, the export view from the current procedure step is matched to the import view of the procedure step to which the flow will take place. Data view matching is discussed in the chapter “Designing the Procedure Logic.”
7	If the dialog flow has the Execute First property, the import data view for the new procedure is passed to its Procedure Action Diagram. Otherwise, the contents of the import data view are placed on the display. The Execute First property is described in Choosing a Flow Action.

In one special case, it is possible to shortcut this cycle by avoiding the execution of the Procedure Action Diagram (step 3), as described in Autoflows.

This description of procedure step execution reveals that the Procedure Action Diagram is essentially independent of the display and dialog flow.

Note:

No explicit actions are required to accept and display displays.

No explicit actions are required to initiate dialog flows.
No special logic is required to detect whether the Procedure Action Diagram was initiated from a display or a dialog flow, or whether the result of its execution is to show a display or initiate a dialog flow.

With most database management systems, any requests for update are saved in some type of temporary storage, and the database is not physically updated until a commit point is reached. Each procedure step execution should be seen as a commit unit, sometimes known as a “success unit.” When execution finishes, stored data is updated to reflect the create, modify and delete actions initiated during the execution just completed. Where several procedure steps must execute to bring all stored data to a consistent state, you specify procedure step logic to ensure that required data consistency is maintained.