Oracle server Default DBA Accounts

SYS CHANGE_ON_INSTALL SYS owns the data dictionary tables, the
place where all the information about
database objects is stored. You should only
connect to the database as SYS if you are
explicitly instructed to do so in this book
or in the Oracle documentation.
SYSTEM MANAGER SYSTEM was originally created to maintain
database objects that support the Oracle
Developer suite of tools. SYSTEM can perform
most of the actions that SYS can and
will be used most of the time for the exercises
in this book.
INTERNAL ORACLE (in some INTERNAL is not truly a database
environments, account, but is used when performing
INTERNAL) certain maintenance work against—and
starting and stopping—the database. Note
that for this book’s exercises, if you are
prompted for a password when connecting
INTERNAL use the password ORACLE (as
shown in the createdb00_01.sql script
below). Oracle states that connecting
INTERNAL will no longer be supported as
of Oracle version 8.2. From then on, you
will connect as SYS AS SYSDBA.