Process Control Files
A process can operate on the data that is contained in any number of files through use of ILF routines, but it can automatically manage only one file. This automatically managed file is referred to as the process control file (PCF) and it applies to input, output, update, query, and inquiry processes. For example, the PCF for a customer maintenance input process is the customer file. APPX automatically reads the PCF while executing the process. In addition, for input processes only, APPX automatically writes, rewrites, and deletes records in the PCF as a function of process execution.
If you want to automatically maintain more than one file, such as entering sales order header information and line item information together, create a separate process for each file and link them together. For example, invoke the line item process as an automatic childfrom the sales order header process. APPX also provides for updating the child PCF for automatic children of input processes to ensure relational integrity. See the following sections, Automatic and Optional Child Invocation and Process Lineage, for additional information on parent and child processes.
A PCF is optional for input and output processes. An input process that does not include a PCF will execute once, and then automatically end (as opposed to executing once for every record). Output processes that do not specify a PCF can be used, for example, to produce standardized page headings and page footers.
Update, query, and inquiry processes must have a process control file. Menu, job, status, and subroutine processes cannot have a PCF.
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