Alter Table syntax Assignment - sql

Question

I have Assignment due in which i'm stuck on a question.
Add a “Sales Detail” table to your database. This table is related to the Orders and Products tables. It shows the product and quantity ordered at least (add other fields if you wish but explain why you added them on your paper).
There is no description of this table on the diagram provided. Use your best database design skills here!
Create Table SalesDetail
(
SaleDetailID int,
ProductID char(5),
ManufactureID char(3) not null,
OrderNo int,
qtyOrdered int
PRIMARY
)
Alter Table SalesDetail
Add FOREIGN KEY (ProductID)
REFERENCES Products(ProductID)
My Error is I can not get it to link SalesDetail table to Products table.
Msg 1776, Level 16, State 0, Line 1
There are no primary or candidate keys in the referenced table 'Products' that match the referencing column list in the foreign key 'FK__SalesDeta__Produ__5EBF139D'.
Msg 1750, Level 16, State 0, Line 1
Could not create constraint. See previous errors.
Create Table Customers
(
CustomerNo char(4)
Constraint ck_CustomerNoHas4positionsWithNumbers
Check(CustomerNo like'[0-9],[0-9],[0-9],[0-9]'),
Company varchar(50) not null,
CustomerRep char(3),
CreditLimt money default(20000.00),
PRIMARY KEY(CustomerNo)
)
Create Table Salesreps
(
EmployeeNo char(3)
Constraint ck_EmployeeNoHasDigits check(EmployeeNo like'[0-9],[0-9],[0-9]'),
FirstName varchar(25) not null,
LastName varchar(25) not null,
Age int,
SalesRepOffice char(2) not null,
Title varchar(50),
HireDate Date not null,
Manager char(3) not null,
Quota money,
Sales money not null,
PRIMARY KEY(EmployeeNo)
)
Create Table Offices
(
Office char(2) Constraint ck_checkOfficeHasNumbersOnly check(Office like'[0-9],[0-9]'),
City varchar(25) not null,
Region varchar(10) not null,
Manager char(3) not null,
Target money,
Sales money not null
PRIMARY KEY(Office)
)
Create Table Orders
(
OrderNo int,
OrderDate Date not null,
CustomerNo char(4) not null,
SalesRep char(3) not null
PRIMARY KEY(OrderNo)
)
Create Table Products
(
ManufactureID char(3)
Constraint ck_ManufactureIDifItHasLettersOnly check(ManufactureID like'[a-z],[a-z],[a-z]'),
ProductID char(5)
Constraint ck_ProductIDhasTwoLettersAndThreeNumbers check(ProductID like'[0-9],[0-9],[a-z],[a-z],[a-z]'),
Description varchar(50) not null,
Price money not null,
QtyOnHand int not null,
PRIMARY KEY(ManufactureID, ProductID)
)
--Add Foreign Keys to all tables who needs them
Alter Table Customers
Add constraint fk_customerrep
FOREIGN KEY (CustomerRep)
REFERENCES Salesreps(EmployeeNo)
Alter Table Salesreps
Add constraint fk_salesrepoffice
FOREIGN KEY (SalesRepOffice)
REFERENCES Offices(Office),
constraint fk_manager
FOREIGN KEY (Manager)
REFERENCES Salesreps(EmployeeNo)
Alter Table Offices
Add constraint fk_officesmanger
FOREIGN KEY (Manager)
REFERENCES Salesreps(EmployeeNo)
Alter Table Orders
Add constraint fk_customerno
FOREIGN KEY (CustomerNo)
REFERENCES Customers(CustomerNo),
constraint fk_salesrep
FOREIGN KEY (SalesRep)
REFERENCES Salesreps(EmployeeNo)

Answer 1

The table Products has a composite key (ManufactureID, ProductID), so you cannot uniquely identify a product by just the ProductId. Therefore you have to create a composite foreign key that references to both ManufactureId and ProductID:
Alter Table SalesDetail
Add FOREIGN KEY (ManufactureId, ProductID)
REFERENCES Products(ManufactureID, ProductID)

Answer 2

ProductID is not a primary key like the error says. In your code
PRIMARY KEY(ManufactureID, ProductID)
This creates a primary key that both of those columns combined.

Answer 3

The primary key for Products is (ManufactureID, ProductID). So the SalesDetail table should contain both these columns, and both should be part of the foreign key constraint:
Alter Table SalesDetail
Add FOREIGN KEY (ManufactureID, ProductID)
REFERENCES Products(ManufactureID, ProductID)