OLD Context Variables

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Indicates a current column value in an UPDATE or DELETE operation. Available in triggers only.

OLD.column
Argument Description

<column>

Name of a column in the affected row

Description: Triggers support two context variables: OLD and NEW. An OLD context variable refers to the current or previous value of a column in an INSERT or UPDATE operation.

Context variables are often used to compare the values of a column before and after it is modified. Context variables can be used anywhere a regular variable can be used.

Example: The following script is a trigger that fires after the EMPLOYEE table is updated, and compares an employee’s old and new salary. If there is a change in salary, the trigger inserts an entry in the SALARY_HISTORY table.

CREATE TRIGGER SAVE_SALARY_CHANGE FOR EMPLOYEE
AFTER UPDATE AS
BEGIN
IF (OLD.SALARY <> NEW.SALARY) THEN
INSERT INTO SALARY_HISTORY
(EMP_NO, CHANGE_DATE, UPDATER_ID, OLD_SALARY, PERCENT_CHANGE)
VALUES (OLD.EMP_NO, NOW, USER, OLD.SALARY,
(NEW.SALARY - OLD.SALARY) * 100 / OLD.SALARY);
END ;

See Also

For more information about creating triggers, see CREATE TRIGGER.

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