SQL - Triggers
Overview
Triggers fire automatically on INSERT/UPDATE/DELETE. Use with care to avoid hidden side effects.
CREATE TABLE audit (msg VARCHAR(255));
DELIMITER //
CREATE TRIGGER trg_emp_insert AFTER INSERT ON employees
FOR EACH ROW
BEGIN
INSERT INTO audit(msg) VALUES (CONCAT('Inserted id ', NEW.id));
END //
DELIMITER ;
DROP TRIGGER trg_emp_insert;
CREATE TABLE audit (msg NVARCHAR(255));
GO
CREATE TRIGGER trg_emp_insert ON dbo.employees
AFTER INSERT AS
BEGIN
INSERT INTO audit(msg) SELECT CONCAT(N'Inserted id ', i.id) FROM inserted i;
END
GO
DROP TRIGGER trg_emp_insert;
CREATE TABLE audit (msg TEXT);
CREATE TRIGGER trg_emp_insert AFTER INSERT ON employees
BEGIN
INSERT INTO audit(msg) VALUES ('Inserted id ' || NEW.id);
END;
DROP TRIGGER trg_emp_insert;