Oracle Forms Developer – Form Builder Reference, Volume 1

On-Message trigger
Description
Fires whenever Form Builder would normally cause a message to display and pre-empts the message.
Definition Level form, block, or item
Legal Commands
SELECT statements, unrestricted built-ins
Enter Query Mode yes
Usage Notes
Use an On-Message trigger for the following purposes:
• to trap and respond to an informative message
• to replace a standard informative message with a custom message
• to exclude an inappropriate message
• Use the MESSAGE_CODE, MESSAGE_TEXT, MESSAGE_TYPE built-ins in an On-Message
trigger to identify the occurrence of a specific message condition.
• If you use the On-Message trigger to trap a message so that it does not display on the message line,
the GET_MESSAGE built-in does not return a value. To display the current message from this
trigger, you must trap the message and explicitly write it to the display device.
• In most cases, On-Message triggers should be attached to the form, rather than to a block or item.
Trapping certain errors at the block or item level can be difficult if these errors occur while Form
Builder is performing internal navigation, such as during a Commit process.
On Failure
no effect
On-Message trigger examples
Example
The following example responds to an error message by displaying an alert that gives the user a message
and gives the user the choice to continue or to stop:
DECLARE
alert_button NUMBER;
lv_errtype VARCHAR2(3) := MESSAGE_TYPE;
lv_errcod NUMBER := MESSAGE_CODE;
lv_errtxt VARCHAR2(80) := MESSAGE_TEXT;
BEGIN
IF lv_errcod = 40350 THEN
alert_button := Show_Alert(’continue_alert’);
IF alert_button = ALERT_BUTTON1 THEN
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