Scenario:
In previous posts, we learn that if we have Foreign key Constraint with default setting and we try to update the value in column in Reference Table which is used as Reference Column in Foreign Key Constraint, we get error. We discussed multiple ways to handle the situation, please check this link.
Foreign Key Constraint does provide the option to set the Cascading action, we can create Foreign Key Constraint with Cascading Update.
If Update Cascading settings is used, when we update the value in Referenced Table , it will also update the value in parent table (Foreign Key Table) column.
Let's test this scenario. Create two tables dbo.Customer and dbo.Orders with Foreign Key Relationship by given script
USE YourDatabaseName
GO
CREATETABLE dbo.Customer (
Customerid INTPRIMARYKEY
,FName VARCHAR(100)
,LName VARCHAR(100)
,SSN VARCHAR(10)
)
CREATETABLE dbo.Orders (
OrderId INTIdentity(1, 1)
,OrderitemName VARCHAR(50)
,OrderItemAmt INT
,Customer_id INTFOREIGNKEYREFERENCES
Customer(CustomerId) ONUPDATECASCADE
)
--insert sample data
insertinto dbo.Customer
(CustomerId,FName, LName,SSN)
values
(1,'Aamir','Shahzad','000-000-00')
insertinto dbo.Orders
(OrderItemName,OrderItemAmt,Customer_Id)
values ('TV',1,1)
Let's check the data in tables by using select query
 |
| How to create Foreign Key Constraint with Update Cascade in SQL Server |
Let's run our update statement on CustomerId in dbo.Customer table and see if it also update the column value in dbo.Orders for Customer_id.
update dbo.Customer
set Customerid=100
Let's check the data again in our tables
 |
| How to enable Update Cascading with Foreign Key Constraint in SQL Server |
As we can see that the value is also updated in dbo.Orders.Customer_id column.