CREATE TABLE IF NOT EXISTS payroll_audit_logs (
  id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
  tenant_id BIGINT UNSIGNED NOT NULL,
  location_id BIGINT UNSIGNED NULL,
  payroll_period_id BIGINT UNSIGNED NOT NULL,
  action VARCHAR(40) NOT NULL,
  actor_user_id BIGINT UNSIGNED NULL,
  note TEXT NULL,
  meta_json LONGTEXT NULL,
  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (id),
  KEY idx_payroll_audit_period (tenant_id, payroll_period_id, created_at),
  KEY idx_payroll_audit_action (tenant_id, action, created_at),
  CONSTRAINT fk_payroll_audit_location FOREIGN KEY (location_id) REFERENCES locations(id) ON DELETE SET NULL,
  CONSTRAINT fk_payroll_audit_period FOREIGN KEY (payroll_period_id) REFERENCES payroll_periods(id) ON DELETE CASCADE,
  CONSTRAINT fk_payroll_audit_actor FOREIGN KEY (actor_user_id) REFERENCES users(id) ON DELETE SET NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;