database - Limit SQL Server column to a list of possible values

Question

How do I put a constraint on a column so that it can only contain the following values? What do you call this type of constraint?

Allowed values: "yes", "no" or "maybe"
Column Data Type: nvarchar(5)
DBMS: SQL Server 2008

question from:https://stackoverflow.com/questions/11981868/limit-sql-server-column-to-a-list-of-possible-values

Answer 1

you can use a CHECK constraint

ALTER TABLE <table>
ADD CONSTRAINT chk_val CHECK (col in ('yes','no','maybe'))

MSDN link