Session mode enables users to establish database sessions (that is, connect to a Nucleus database instance), change from one session to another, and disconnect database sessions. The .SESS system command enables users currently in SQL mode to access ssasql Session mode and execute Session mode commands.

When ssasql is invoked without connection name, database name, and user name arguments, or if any of the specified arguments is invalid, the user is automatically placed in Session mode. The CONNECT command can subsequently be used to establish a database session.