Forms

Used to share the code across the modules.
These are stored in PLL files.
When PLL file is compiled, PLX file is generated.

Pl/SQL Libraries generally contain procedures, functions and packages.

Creating PL/SQL Library

Open the form builder tool
File Connect Provide User Name , password and database details to establish connection.

Select PL/SQL  Libraries Click on Create

Select Program units Click on create Name --    add_num Types Select Function OK

Provide the following code and compile

function add_num (  a number, b  number) return  number
is
r  number(12);
begin
select a+b into r from dual;
return r;
end;

Lets create another function

In the Object Navigator

Under Pl/SQL Libraries Under Program units Click on create button

Name --    mul_num Types Select Function OK

Provide the following code and compile

function mul_num ( x  number,  y  number)
return number
is
r  number(12);
begin
select  x*y  into r from dual;
return  r;
end;

Lets create another function

In the Object Navigator

Under Pl/SQL Libraries Under Program units Click on create button

Name --    sub_num Types Select Function OK

function sub_num ( n  number, m  number)
return number
is
r  number(12);
begin

select  n-m into r from dual;
return r;
end;

So, our library is having three functions.

Now, Go to File   Save as  TEST.pll
Program Compile Module
Observe PLX file is generated.
Exit from the Form Builder tool.

Using Libraries in Forms

Open the from builder tool Build new form manually

In the Object Navigator
select Attached Libraries Click on create Browse Select TEST.pll Attach

We get the following Alert

Click on No
As we have attached, we can see the functions in our form.

Select Data Blocks Click on create button Select build a new Data Block manually OK
Provide the following properties

General
Name --  MY_BLOCK1
Database
Database Data Block -- No

Note
When we set the property Database Data Block to No, It is called as Control Block.

In Object Navigator
Select Canvas Click on Create button
Provide following properties

General
Name -- MY_CANVAS1

Go to the Layout editor
Place two text items , four buttons and a display item.

Name the two text items as T1 and T2

Name the buttons as B1 , B2, B3 and B4

Provide the following label respectively

For B1 label it as  ADD
For B2 label it as MULTIPLY
For B3 label it as MINUS
For B4 label it as CLEAR

Name the Display Item as D1, Prompt as Result

Create WHEN-BUTTON-PRESSED for the button B1 and provide the following code and compile.

:D1 := add_num (:T1, :T2);

Create WHEN-BUTTON-PRESSED for the button B2 and provide the following code and compile.

:D1 := mul_num (:T1, :T2);

Create WHEN-BUTTON-PRESSED for the button B3 and provide the following code and compile.

:D1 := sub_num (:T1, :T2);
Create WHEN-BUTTON-PRESSED for the button B4 and provide the following code and compile.

clear_block;
go_item('T1');

Save the form with the name CALCULATE.fmb

Compile the form.
Run the form.

Check the functionality.

Advantage
Provides security while sharing code between modules ( Code is hidden ).
Reusability of the code.
Faster in execution.