This class is used to generate and manage sessions. A
provides a context for database transactions and operations.
Each independent user should have its own session.
openSession(Object mappings, Function(Object error, Session session) callback);
Open a database session object. Table
mappings are validated at the
beginning of the session. Resources required for sessions are
allocated in advance; if those resources are not available, the
method returns an error in the callback.
Get all open sessions that have been created by this
Close the connection to the database. This ensures proper disconnection. The function passed in is called when the close operation is complete.