Compound Primary key is a primary key which is created on more than one column. Now the questions is how to create the foreign key for the compound primary key where it references more than one column.
Check the below example.
create table employee
(
empID int not null,
SSN int not null,
name varchar(20)
)
ALTER TABLE [employee]
ADD CONSTRAINT pk_employee PRIMARY KEY (empID, SSN)
create table EmpDetail
(
empID int,
SSN int,
address varchar(20),
city varchar(20),
pin varchar(20)
)
ALTER TABLE dbo.empDetail
ADD CONSTRAINT FK_Employee
FOREIGN KEY(empID, SSN)
REFERENCES dbo.employee(empID, SSN)
SELECT
tc.TABLE_NAME,
tc.CONSTRAINT_NAME,
ccu.COLUMN_NAME
FROM
INFORMATION_SCHEMA.TABLE_CONSTRAINTS tc
INNER JOIN
INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE ccu
ON ccu.TABLE_NAME = tc.TABLE_NAME AND ccu.CONSTRAINT_NAME = tc.CONSTRAINT_NAME
WHERE
tc.TABLE_NAME IN ('employee','employeeDetail')
