When using Microsoft SQL Server, there is this handy thing called dedicated administrator connection. You can tell the database to drop all connections and not open any new ones, but keep the one you use right now alive for administrative purposes.
Is there a similar feature available for IBM's DB2 UDB?
There are a few options:
Quiescing optionally allows you to kill all other connections to the instance (which could apply to multiple databases) or to a single database; but this will not prevent users who have appropriate privileges to reconnect.
Connecting to a database in exclusive mode will allow multiple connections from the same user. You will have to manually kill other user connections first, though.