I have tables:

```
Users{UserId ...}
Professors{UserId ...}

```

I set `UserId` to be PK in both tables and made 1:1 relationship.

But if I try to insert new user it doesn't work as it requires insert in the `Professor` table too.

I want to make that one user can have only 1 record in Professor table but I also want to make it that it doesn't have to exist in Professor table (I don't want to make all users professors :) ).

How to set 1 to (0...1) relationship in SQL Server Management Studio?

I know that set enforce key constraints to NO is not a solution :)