CREATE TABLE IF NOT EXISTS transaction (
	t_id		INT NOT NULL AUTO_INCREMENT,
	type		ENUM("Expense", "Income") NOT NULL,
	date		DATETIME DEFAULT CURRENT_TIMESTAMP,
	quantity	NUMERIC(5,0) NOT NULL,
	p_id		INT,

	PRIMARY KEY	(t_id),
	FOREIGN KEY	(p_id) REFERENCES product(p_id) ON DELETE SET NULL
);