Creating of timers in Oracle Forms

1. Working With Timers
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2. Objectives
• Describe Timer
• Usage of timer
• Create timer
• Modify timer
• Handle timer expiration
• Delete timer
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3. Timers
• What is a timer?
A timer is an "internal time clock" that you programmatically create
to perform an action each time the timer expires.
• Built-ins used:
– FIND_TIMER
– CREATE_TIMER
– SET_TIMER
– DELETE_TIMER
– GET_APPLICATION_PROPERTY
(TIMER_NAME)
http://blog.ebiztechnics.com

4. Usage of Timers
• WHEN-TIMER-EXPIRED Trigger.
• Using timers:
– Periodically query, commit, or rollback
– Show “About…” information at startup
– Display ticker messages
– Display running time
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5. Handling Timer Expiration
Start
(R)
T1
When-Timer-Expired (A)
Query
issued
Timer T2
expired T2
Timer T1
expired
(R)
T2,T1
Completed
When-Timer-Expired (T2)
When-Timer-Expired (T1)
Timer T1
created
Timer T2
created
Timer T1
expired
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6. Creating a Timer
• Syntax:
• Example:
CREATE_TIMER (timer_name, milliseconds, iterate)
v_timer_id := CREATE_TIMER (‘Time1’, 300,repeat);
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7. Modifying a Timer
• Syntax:
• Example:
SET_TIMER (timer_name, milliseconds, iterate)
SET_TIMER (timer_id, milliseconds, iterate)
SET_TIMER (‘Time1’, no_change, no_repeat);
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8. Delete Timer
• Syntax:
DELETE_TIMER (timer_name)
DELETE_TIMER (timer_id)
...
IF NOT ID_NULL (FIND_TIMER (‘Time1’)) THEN
DELETE_TIMER (’Time1’);
END IF;
...
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9. Find Timer Expiration
• Example:
IF GET_APPLICATION_PROPERTY(TIMER_NAME)=‘Time1’
THEN
Select . . . . .
From t1;
ELSE
:control.time_disp:=:SYSTEM.CURRENT_DATETIME;
END IF;
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10. Summary
• Create and modify a timer with built-in
functions
– FIND_TIMER
– CREATE_TIMER
– SET_TIMER
– DELETE_TIMER
– GET_APPLICATION_PROPERTY
(TIMER_NAME)
http://blog.ebiztechnics.com