The components of a process operate in a defined sequence so that there is a consistent pattern of operation, no matter what type of process is defined. For example, if a process has several frames that include optional and automatic children, and many of the frames also contain images, you need to understand APPX's processing sequence to achieve your intended design objective.
The primary control mechanism within a process is a frame. If a process has more than one frame, they operate in sequence based on a number you assign. APPX executes one complete process cycle (all frames one after the other) for each selected record in a process control file. For input processes, users select the records. For update and output processes, records may be selected by a previous query process; otherwise, the entire file is used. Thus, for an update or output process, if there are 100 selected records from the PCF, the entire frame cycle will execute 100 times.
A frame may include an image (or several alternate images), and invoke one or more automatic children, as well. APPX executes all the components of one frame before proceeding to the next.
Child processing is controlled in two fundamentally different ways. An optional child is always invoked by a user selecting an option key, and is always invoked from an image. An automatic child is invoked at the appropriate time without user intervention. For example, as soon as a user finishes entering data for an order in an order entry input process, a line item input process may automatically be invoked when the user selects Enter .
Because of the basic difference between optional and automatic children as described above, there is not a conflict with the order of invocation. Because a child is also a process, it can include a number of its own components. The same rules regarding order of invocation as described previously also apply for a process that is itself a child. You can therefore design a process that has various levels for which the sequence of operation is always predictable.
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