Database Triggers untuk Otomasi & Audit Log

-- Membuat tabel audit riwayat perubahan gaji
CREATE TABLE audit_gaji (
    audit_id SERIAL PRIMARY KEY,
    employee_id INT,
    gaji_lama NUMERIC(12, 2),
    gaji_baru NUMERIC(12, 2),
    diubah_pada TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- Membuat Trigger otomatis saat kolom gaji di-UPDATE
CREATE TRIGGER log_perubahan_gaji
AFTER UPDATE OF gaji ON employees
FOR EACH ROW
WHEN (OLD.gaji IS DISTINCT FROM NEW.gaji)
EXECUTE FUNCTION catat_audit_gaji();