database design - SQL-Server: Define columns as mutually exclusive -

By joking with a collage, I came from an interesting scenario: is it possible that SQL Server defines a table So that "standard meanings" (obstacles, etc.) can I make sure that two or more columns are mutually exclusive?

I mean: can I make sure that only one of the columns is included in the column?

Yes, you can use a check barrier:

  ALTER TABLE YourTable ADD  
  contract obligation check (call 1 blank or call 2 is empty)  
 
 According to your comment, if multiple columns are unique, You can check them like this: 
 
  When call 1 is zero then 0 and 1 end + case when call 2 is zero, then 0 and 1 end + case when call 3 is zero , Then 0 and 1 end + case when call 4 is zero, then 0 and 1 end = 1  
 
 say this Land should be one of the values ​​of the four columns. If they can all be taped, then simply  & lt; = 1 .