Define acceptable values for column

Hi

I havea user column in my table. I want the the value of this to be limited to "User1", "User2" or "user 3". Is there a way in SQL that I can define these 3 values to be in a dropdown in the field when I choose that field?

Thanking you in advance

PORRASTAR

Maybe if you use a inne join to a table that contains those 3 values.