Specify both dbuser and dbname to control how Adaptive Server executes the query. These variables can affect the process:
In the user context of the specified login when that login is a valid user in the specified database
In the user context of “guest” when the login is not a valid user in the specified database
When the specified database is a system database, a “guest” account always exists. However, when the specified database is a user database, the database owner must have ensured that:
The entity represented by the dbuser login is a valid database user, or
There is a “guest” user in the database that can map to any login and execute queries with minimal permissions.