Beginning Microsoft SQL Server 2008 ... - S3 Tech Training

Chapter 6: Constraints
So we have a CustomerID of 1 (your number may be different depending on what experimentation you’ve
done). We’ll take that number and use it in our next INSERT (into Orders, finally). Let’s insert an order
for CustomerID 1:
INSERT INTO Orders
(CustomerNo, OrderDate, EmployeeID)
VALUES
(1, GETDATE(), 1);
This time, things should work fine.
It’s worth noting that the reason we don’t still get an error here is that we already
inserted that primer row in the Employees table; otherwise, we would have needed
to get a row into that table before SQL Server would have allowed the insert into
Orders (remember that Employees foreign key?).
At this point, we’re ready for our insert into the OrderDetails table. Just to help with a CASCADE example
we’re going to be doing in a moment, we’re actually going to insert not one, but two rows:
INSERT INTO OrderDetails
VALUES
(1, ‘4X4525’, ‘This is a part’, 25.00, 2)
INSERT INTO OrderDetails
VALUES
(1, ‘0R2400’, ‘This is another part’, 50.00, 2);
So, let’s verify things by running a SELECT:
SELECT OrderID, PartNo FROM OrderDetails;
This gets us back to our expected two rows:
OrderID PartNo
--------- ---------
1 0R2400
1 4X4525
(2 row(s) affected)
Now that we have our data entered, let’s look at the effect a CASCADE has on the data. We’ll delete a row
from the Orders table, and then see what happens in OrderDetails:
USE Accounting
-- First, let’s look at the rows in both tables
SELECT *
FROM Orders;
SELECT *
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