Adding a Constraint to a SQL Server DB field to ensure that the field contains a particular string

  This was an interesting problem. What if, for some strange reason, you wanted to make sure that a field contained a certain string or it didn't get inserted? This can be handled pretty easily on the front end, but just for fun, let's try doing it on the back end:

-- Unrealistic, I'm sure. Let's just say that we ONLY want people
-- with Gmail email addresses adding their emails into our table.

ALTER TABLE myTable
WITH CHECK ADD
CONSTRAINT [ValidEmail]
CHECK
(
Email LIKE '%@gmail.com'
)
GO