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\"         


        

Answer 1

Yes, check a constraint is it what you need. You can declare check constraint at the table declaration:

CREATE TABLE test(
    _id BIGINT PRIMARY KEY NOT NULL,
    decision NVARCHAR(5),
    CHECK (decision in ('yes','no','maybe'))
);