Sql 关系1到n

我找不到与此相关的错误，它显示了添加此关系的外键错误。任何人请帮忙。

删除中的

至

create database shop1
use shop1

create table mathang
(
       MatHangID  INT primary key not null,
       TenMatHang varchar(50),
       SoLuong    int not null,
       Price      int not null,
)

create table nhacungcap
(
       MatHangID  INT foreign key references mathang,
       TenNhaCungCap varchar(50) ,
       DiaChi        varchar(100),
       SoDienThoai   int ,
       CONSTRAINT pk_M_CC primary key (MatHangID)
)

create table khachhang
(
       KhachHangID   int not null primary key,
       TenKhachHang  varchar(50)  not null,
       [DiaChi]      varchar(100) not null,
       [SoDienThoai] varchar(50)  not null,
)

create table donhang
(
       DonHangID int references to khachhang(KhachHangID),
       TenDonHang    varchar(50),
       SoLuong       int,
       CONSTRAINT pk_DHID primary key (DonHangID)
)

得到

...
DonHangID int references to khachhang(KhachHangID)
...

。

to

在语法上不属于那里

...
DonHangID int references khachhang(KhachHangID)
...