Oracle Forms: Introduction to multiple Forms

Introduction to Multiple Form Applications
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Objectives
• Call one form from another from module
• Define Multiple form functionality

Multiple Form Applications
• Behavior:
– Flexible navigation between windows
– Single or multiple database connections
– Transactions may span forms, if required
– Commits in order of opening forms, starting with current form
• Links:
– Data is exchanged by global variables or parameter lists
– Code is shared as required, through libraries and the database

Multiple Form Sessions
Form A
Forms
Runtime
Global variables
Form B
Open
Form C
Open
Form D
Open

OPEN_FORM Built-in
MDI
FORM A
MDI
FORM A
Modeless
FORM B
OPEN_FORM

Implementing Multiple Forms
1. Define windows and positions for each form.
2. Plan global variables and their names.
3. Implement triggers to:
• Open other forms
• Initialize global variables from calling forms
• Use global variables in opened forms

Linking by Global Variables
Employees
Departments
GLOBAL.dept_id
Deptno

Opening Another Forms
:GLOBAL.dept_id:=:DEPT.deptno;
OPEN_FORM(‘employees’);
• Control passes immediately to the Employees form—no statements
after OPEN_FORM are processed.
• If the Activate_Mode argument is set to NO_ACTIVATE, you retain
control in the current form.
• The transaction continues unless it was explicitly committed before.

Restricted Query at Startup
Execute_Query;
:EMP.deptno := :GLOBAL.dept_id;
When-New-Form-Instance - Form Level
Pre-Query - Block Level

Global Variables in Opened Form
• Assign Global variables values in opened form with
DEFAULT_VALUE Built-in.
• DEFAULT_VALUE ensures the existence of global variables.
• You can use global variables to communicate that the form is running.
• Pre-Form Example:
DEFAULT_VALUE(‘ ‘,‘GLOBAL.dept_id’);

Conditional Opening
:GLOBAL.dept_id := :DEPT.deptno;
IF ID_NULL(FIND_FORM(’EMPLOYEES’)) THEN
OPEN_FORM(’EMPLOYEES’);
ELSE
GO_FORM(’EMPLOYEES’);
END IF;

Closing a Form with EXIT_FORM
• The default functionality is the same as for the Exit key.
• The Commit_Mode argument defines action on uncommitted changes.
ENTER;
IF :SYSTEM.FORM_STATUS = ’CHANGED’ THEN
EXIT_FORM( DO_COMMIT );
ELSE
EXIT_FORM( NO_COMMIT );
END IF;

Summary
• The OPEN_FORM built-in provides multiple concurrent
forms in a session.
• Forms communicate through global variables:
– Load key values in the parent form
– Use global values in opened forms for
When-New-Form-Instance and Pre-Query

Oracle Forms: Introduction to multiple Forms

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