Global Constant-Package

When you need literals and constants in forms, then the easiest way is to hardcode it in the sourcecode.

But please never do it the easiest way !

Have a look at this source-snippets and get a feeling, how to use them in your own code :

All my forms have attached libraries, in which I store my framework-functions.

One package spec. in this library is the package CONST. This package has no package body.

PACKAGE Const IS
/*
|| Name : Const
||
|| Function : This package contains all global Constants
||
|| Author : 08.08.1999, VOL
|| Updates :
*/

-- Alert
  alr_Error     CONSTANT VARCHAR2 (30) := 'AL_ERROR';
  alr_Info      CONSTANT VARCHAR2 (30) := 'AL_INFO';
  alr_Warning   CONSTANT VARCHAR2 (30) := 'AL_WARNING';

-- Mode
  mod_Call_Form CONSTANT VARCHAR2 (10) := 'CALL_FORM';
  mod_Open_Form CONSTANT VARCHAR2 (10) := 'OPEN_FORM';
  mod_Go_Form   CONSTANT VARCHAR2 (10) := 'GO_FORM';
  mod_New_Form  CONSTANT VARCHAR2 (10) := 'NEW_FORM';

-- Block, Record and Form-Status
  sta_Changed   CONSTANT VARCHAR2 (10) := 'CHANGED';
  sta_Insert    CONSTANT VARCHAR2 (10) := 'INSERT';
  sta_New       CONSTANT VARCHAR2 (10) := 'NEW';
  sta_Query     CONSTANT VARCHAR2 (10) := 'QUERY';

-- Other
  CR            CONSTANT VARCHAR2  (1) := CHR (10);
  Tab           CONSTANT VARCHAR2  (1) := CHR (9);
  TRUE          CONSTANT VARCHAR2 (10) := 'TRUE';
  FALSE         CONSTANT VARCHAR2 (10) := 'FALSE';

END Const;

This is only a very short part of my complete Const-package

All sourcecodes in which I now need a literal I change this to a constant from this package

e.g.

IF NAME_IN ('System.Last_Record') = Const.TRUE THEN
--do something;
ELSE
--do something different;
END IF;

This method of using a const-package can be enhanced, if you create another const-package in each form. Name it const_local.

PACKAGE Const_local IS
/*
|| Name : Const_local
||
|| Function : local Constant-Package
||
|| Author : 08.08.1999, VOL
|| Updates :
*/

-- Blocks
  blk_Control CONSTANT VARCHAR2 (30) := upper ('Control');

-- Items
  itm_Test    CONSTANT VARCHAR2 (61) := upper ('Control.TI_TEST');

END Const_local;

With this local package you can now handle all the literals which are needed only in the form. This package can rapidly grow and is the central place for all other functions and procedures.

These packages offer some very important opportunities. All your literals are now constants. That means you have never runtime-errors, when you write a typo. You now have always compile-time-errors.

If you write a literal incorrect, than there is only one place in the const-package, where the constant is defined and the error can occur. Those error may occur, but they are found very fast and can be corrected directly.


Conclusion: Use the global Const-package in a library and use the local-package for all needs you have in the form itself.

Try and use it