Trigger

From Oracle FAQ

A trigger is a program in a database that gets called each time a row in a table is INSERTED, UPDATED, or DELETED. Triggers allow you to check that any changes are correct, or to fill in missing information before it is COMMITed. Triggers are normally written in PL/SQL or Java.

Example

CREATE TABLE t1 (c1 NUMBER);
CREATE TABLE audit_log(stamp TIMESTAMP, usr VARCHAR2(30), new_val NUMBER);

CREATE TRIGGER t1_trig
  AFTER INSERT ON t1 FOR EACH ROW
BEGIN
  INSERT INTO audit_log VALUES (SYSTIMESTAMP, USER, :NEW.c1);
END;
/

Also see

• Procedure
• Function
• Package

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