At the time the database is created, an initial profile named DEFAULT is established. This is the default profile, and has two functions:
To act as the default profile for a user where no profile is specified
To act as a definition of default values for other profiles
Any of the parameters documented above can have a specified value DEFAULT. Oracle uses the value specified in the DEFAULT profile for that parameter. This process is repeated each time a user connects, so a change to the DEFAULT profile will automatically take effect with the next connection.