CREATE TRIGGET to auto update quantity of an item when it is inputted from another table

See more:

SQL

trigger

I have three tables like:

CREATE TABLE SACH(
	MaSach			VARCHAR(20) PRIMARY KEY,
	TenSach			VARCHAR(50) NOT NULL,
	TacGia			VARCHAR(30) NOT NULL,
	NgayXuatBan		DATETIME	NOT NULL,
	NhaXuatBan		VARCHAR(30) NOT NULL,
	CurrentQuantity INT	NOT NULL,
	MaLoai			VARCHAR(10) FOREIGN KEY REFERENCES LOAI(MaLoai),
	MaNCC			VARCHAR(20) FOREIGN KEY REFERENCES NHACUNGCAP (MaNCC)
)

CREATE TABLE NHAPKHO(
	MaNhapKho		VARCHAR(10) PRIMARY KEY,
	NgayNhap		DATETIME	NOT NULL,
)

CREATE TABLE CHITIETNHAPKHO(
	MaNhapKho		VARCHAR(10) FOREIGN KEY REFERENCES NHAPKHO(MaNhapKho),
	MaSach			VARCHAR(20) FOREIGN KEY REFERENCES SACH(MaSach),
	Quantity                INT			NOT NULL	CHECK(SoLuong >0),
	GiaNhap			FLOAT		NOT NULL,
								PRIMARY KEY (MaNhapKho, MaSach)
)

.

We can see that the table CHITIETDATHANG foreign to SACH and NHAPKHO.
In fact, when we insert value of Quantity column into CHITIETNHAPKHO, CurrentQuantity column in SACH is auto updated. And I would like to create a trigger to do this task.