A function defines a list of processes that will operate on the files and fields in your database.
CA 2E provides a variety of standard functions to which you can add your own unique processing.
The set of standard functions consist of database functions, device functions, and user functions.
A function can be implemented either as a separate program or as a subroutine within a program as follows:
■ An external function is implemented as a separate high-level language (HLL) program. Each external function is attached to an access path. In general, the standard device functions are external functions; for example, the Edit File function. The only exception is the Print Object (PRTOBJ) function that is covered in a later chapter of this tutorial.
■ An internal function is implemented as source code within that of the calling program; in other words, it is implemented as a subroutine. All the standard database functions are internal functions; for example, the Create Object function
A function is a unit of specification, not implementation.
Several internal functions may be implemented as a single program.
Components of a standard functions: (Note that not all function types have all four components)
■ Device design—Specifies the layout of the panel or report used by the function
■ Action diagram—Specifies the processing steps that make up the function (includes default processing and processing that you define)
■ Function options—Specifies default features of a function
■ Function parameters—Specifies fields to be passed into the function and returned from the function at run time
In addition to the standard functions, CA 2E provides message functions, function fields, and built-in functions, which perform low-level processing such as arithmetic operations.
List of different Function Types:
Internal Functions:
Change object CHGOBJ
Create object CRTOBJ
Delete object DLTOBJ
Retrieve object RTVOBJ
Print object PRTOBJ
External Functions (screens):
Display file DSPFIL
Display record(1 screen) DSPRCD
Display record(2 screen) DSPRCD2
Display record(3 screen) DSPRCD3
Display transactions DSPTRN
Edit file EDTFIL
Edit record(1 screen) EDTRCD
Edit record(2 screens) EDTRCD2
Edit record(3 screens) EDTRCD3
Edit transaction EDTTRN
Prompt & validate record PMTRCD
Select record SELRCD
External Functions (non-screens):
Execute external function EXCEXTFUN
Execute internal function EXCINTFUN
Execute user program EXCUSRPGM
Execute user source EXCUSRSRC
Print file PRTFIL
CA 2E automatically creates five default functions for each reference file (REF) you declare: two external functions (Edit File and Select Record), and three internal functions (Change Object, Create Object, and Delete Object).
Note that for capture files (CPT), CA 2E automatically creates only the three internal functions (Change Object, Create Object, and Delete Object).
Take F on a file to access the functions which are created based on a particular file.
These are the functions based on this file:
These are the list of different type of functions:
Function type Classification:
*EXT : Function will be implemented as a s eparate program.
*INT : Function will be implemented as in-line code within a calling program.
*DEV : Function type has a device file.
*DBF : Function type is a databse update routine.
*USR : Function type is user defined.
*SCR : Function type has a screen device file.
*RPT : Function type has a report device file.
*DSP : Function type is display only.
*UPD : Function type updates the database.
*WS : Function type models a web service.