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

When we run this, we have a problem:
Msg 547, Level 16, State 0, Line 1
The ALTER TABLE statement conflicted with the CHECK constraint
“CN_CustomerPhoneNo”. The conflict occurred in database “Accounting”, table
“dbo.Customers”, column ‘Phone’.
SQL Server does not create the constraint unless the existing data meets the constraint criteria. To get
around this long enough to install the constraint, either we need to correct the existing data or we must
make use of the WITH NOCHECK option in our ALTER statement. To do this, we just add WITH NOCHECK to
the statement as follows:
ALTER TABLE Customers
WITH NOCHECK
ADD CONSTRAINT CN_CustomerPhoneNo
CHECK
(Phone LIKE ‘([0-9][0-9][0-9]) [0-9][0-9][0-9]-[0-9][0-9][0-9][0-9]‘);
Now if we run our same INSERT statement again (remember it inserted without a problem last time), the
constraint works and the data is rejected:
Msg 547, Level 16, State 0, Line 1
The ALTER TABLE statement conflicted with the CHECK constraint
“CN_CustomerPhoneNo”. The conflict occurred in database “Accounting”, table
“dbo.Customers”, column ‘Phone’.
However, if we modify our INSERT statement to adhere to our constraint and then re-execute it, the row
will be inserted normally:
INSERT INTO Customers
(CustomerName,
Address1,
Address2,
City,
State,
Zip,
Contact,
Phone,
FedIDNo,
DateInSystem)
VALUES
(‘MyCust’,
‘123 Anywhere’,
‘’,
‘Reno’,
‘NV’,
80808,
‘Joe Bob’,
‘(800) 555-1212’,
‘931234567’,
GETDATE());
Chapter 6: Constraints
177