In user databases, the database owner adds a guest user that permits all Adaptive Server users to use that database, which saves the owner from having to use sp_adduser to explicitly name each user as a database user.
You can use the guest mechanism to restrict access to database objects while allowing access to the database.
For example, the owner of the titles table can grant select permission on titles to all database users except “guest” by executing:
grant select on titles to public sp_adduser guest revoke all on titles from guest
