While a trigger is , which determines whether the trigger fires before or after the triggering statement runs and whether it fires for each row that the triggering statement affects. If the trigger is created on a schema or the database, then the triggering event is composed of either DDL or database operation statements, and the trigger is called a )".
By default, a trigger is created in the enabled state. When a trigger fires, tables that the trigger references might be undergoing changes made by SQL statements in other users' transactions.
This can result in significant speedups in statements that modify many rows, if the trigger only needs to be fired for a few of the rows.
In triggers modify rows or prevent updates during an update that is caused by a referential action.
Constraints are easier to write and less error-prone than triggers that enforce the same rules.sal_diff); END; / Whalen: Old salary = 2800, New salary = 2940, Difference: 140 Hartstein: Old salary = 13000, New salary = 13650, Difference: 650 Fay: Old salary = 6000, New salary = 6300, Difference: 300 Kochhar: Old salary = 17000, New salary = 17850, Difference: 850 De Haan: Old salary = 17000, New salary = 17850, Difference: 850 INSERT INTO tab1 VALUES ('Some text.'); CREATE OR REPLACE TRIGGER trg1 BEFORE UPDATE ON tab1 FOR EACH ROW BEGIN DBMS_OUTPUT.PUT_LINE('Old value of CLOB column: '