When you submit a REVOKE LOGON request for one or more user names, Teradata Database creates a logon control record for each user_name/host_ID pair specified.
Any existing control record for a particular pair is replaced. The logon control record set created for a particular user name exists until that user is dropped.
Any attempt to revoke logon privileges for user DBC aborts the request and returns an error. If you attempt to log on to the system as user DBC and you submit the correct password, then the logon is accepted regardless of the current default for the applicable host ID. This prevents any opportunity to lock out all clients from user DBC.