Oracle Forms : Validation Triggers

Validation & Navigational Triggers
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Objectives
• What is Validation Unit?
• Form Builder Validation Properties
• Using triggers to implement Validation
• Navigation in Forms
• Navigation Properties
• Navigational Triggers
• Built-ins used for Navigation

Validation in Form Builder
• Form Builder provides the Validation at 4 Levels:
Form Level
Block Level
Record Level Item Level

Validation
• Validation occurs when:
– Enter key is pressed or ENTER Built-in execute.
– Operator or trigger leaves the validation unit (includes a Commit)

Validation Property
Form Module
Properties -> Database->
Validation Unit

Validate from list
• Text item Property
• Used to validate from LOV
• If the input value does not exist in LOV the List of values window
appears to choose.
• Note: Do not use this property for large number of values.

Validation Triggers
• Item Level
– When-Validate-Item
• Block Level
– When-Validate-Record
IF :emp.ename is null or :emp.hiredate is null THEN
message(‘Employee name or
Joining Date can not be blank’);
RAISE form_trigger_failure;
END IF;

Validating User Input
• Salary Details Form.
7987Emp No When-Validate-Item
SELECT ……….
FROM emp
WHERE empno=:empsal.empno;
Trigger Failure

Validation Status
• NEW
– When a record is created
– Also for Copy Value from Item or Initial Value
• CHANGED
– When changed by user or trigger
– When any item in new record is changed
• VALID
– When validation has been successful
– After records are fetched from database
– After a successful post or commit
– Duplicated record inherits status of source

Built-ins for Validation
• CLEAR_BLOCK, CLEAR_ FORM, EXIT_FORM
• ENTER
• SET_FORM_PROPERTY
– (..., VALIDATION)
– (..., VALIDATION_UNIT)
• ITEM_IS_VALID item property
• VALIDATE (VALIDATION_ UNIT)
SET_FORM_PROPERTY(‘FORM_MOD’,VALIDATION_UNIT,
);ITEM_SCOPE
RECORD_SCOPE / BLOCK_SCOPE / FORM_SCOPE

Navigation in forms
• What is Navigational Unit?
• Navigation in
– Form
– Block
– Record
– Item
• Entering and Leaving Objects
• What happens if navigation fails?

Navigation Properties
• Form module
– Mouse navigation limit
– First navigation data block
• Block
– Navigation style
– Previous navigation data block
– Next navigation data block
• Item
– Enabled
– Keyboard navigable
– Mouse navigate
– Previous navigation item
– Next navigation item

Navigation in Blocks
Exit item
Exit record
Exit block
Enter block
Enter record
Enter item

Internal Navigation
Exit item
Exit record
Enter record
Enter item

Navigational Triggers
When-New-“object”-Instance
Fire after navigation
Does fire when validation unit is
higher than the trigger object
Allow restricted and
unrestricted built-ins
Are not affected by failure
Pre- and Post-
Fire during navigation
Does not fire if validation unit
is higher than trigger object
Allow unrestricted built-ins
Handle failure by returning to
initial object

Pre- and Post- Triggers
• Pre/Post-Form
• Pre/Post-Block
• Pre/Post-Record
• Pre/Post-Text-Item

Example Pre-Block Trigger
IF GET_APPLICATION_PROPERTY(username)=‘SCOTT’ THEN
SET_BLOCK_PROPERTY(‘EMP’,UPDATE_ALLOWED,
Property_False);
END IF;

When-New-”object” Instance
• When-New-Form-Instance
• When-New-Block-Instance
• When-New-Record-Instance
• When-New-Item-Instance

Examples
SET_FORM_PROPERTY(‘EMPL’, VALIDATION_UNIT,
RECORD_SCOPE);
SET_BLOCK_PROPERTY(‘EMP’, QUERY_ALLOWED, PROPERTY_FALSE);
READ_IMAGE_FILE(‘E_’||:emp.empno||’.bmp’,’BMP’,
’emp.emp_image);
SET_ITEM_PROPERTY(:SYSTEM.cursor_item,
visual_attribute, ‘vared’);

Navigational Trap
Pre-Text-Item
Pre-Text-Item
Post-Text-Item

Summary
• Validation Unit
• Triggers and Built-ins for Validation.
– When-Validate-Item and When-Validate-Record
• Validation Properties
• Navigation in Forms
• Internal and External Navigation
• Navigational Triggers
– Pre- , Post- and When-New-”Object”-Instance Triggers

Oracle Forms : Validation Triggers

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