A visitor login ID is a general-purpose login ID. Creating a visitor login on a server enables anyone who knows that login ID and the password to log in to SQL Server. If this is desired, the SA must add a login ID (for example, visitor) and provide that login ID and password to selected users.
A visitor login ID on SQL Server only allows a user to log in to the server. To allow a user access to a database (without adding a username), a guest user must be added to the database. For information, see About Database Users.