Who created all these users in my database?/ Can I drop this user?

Oracle creates a number of default database users or schemas when a new
database is created. Below are a few of them:

SYS/CHANGE_ON_INSTALL or INTERNAL

Oracle Data Dictionary/ Catalog

Created by: ?/rdbms/admin/sql.bsq and various cat*.sql scripts

Can password be changed: Yes (Do so right after the database was created)

Can user be dropped: NO


SYSTEM/MANAGER

The default DBA user name (please do not use SYS)

Created by: ?/rdbms/admin/sql.bsq

Can password be changed: Yes (Do so right after the database was created)

Can user be dropped: NO


OUTLN/OUTLN

Stored outlines for optimizer plan stability

Created by: ?/rdbms/admin/sql.bsq

Can password be changed: Yes (Do so right after the database was created)

Can user be dropped: NO


SCOTT/TIGER, ADAMS/WOOD, JONES/STEEL, CLARK/CLOTH and BLAKE/PAPER.

Training/ demonstration users containing the popular EMP and DEPT tables

Created by: ?/rdbms/admin/utlsampl.sql

Can password be changed: Yes

Can user be dropped: YES - Drop users cascade from all production environments


HR/HR (Human Resources), OE/OE (Order Entry), SH/SH (Sales History).

Training/ demonstration users containing the popular EMPLOYEES and DEPARTMENTS tables

Created by: ?/demo/schema/mksample.sql

Can password be changed: Yes

Can user be dropped: YES - Drop users cascade from all production environments


CTXSYS/CTXSYS

Oracle interMedia (ConText Cartridge) administrator user

Created by: ?/ctx/admin/dr0csys.sql


TRACESVR/TRACE

Oracle Trace server

Created by: ?/rdbms/admin/otrcsvr.sql


DBSNMP/DBSNMP

Oracle Intelligent agent

Created by: ?/rdbms/admin/catsnmp.sql, called from catalog.sql

Can password be changed: Yes - put the new password in snmp_rw.ora file

Can user be dropped: YES - Only if you do not use the Intelligent Agents


ORDPLUGINS/ORDPLUGINS

Object Relational Data (ORD) User used by Time Series, etc.

Created by: ?/ord/admin/ordinst.sql


ORDSYS/ORDSYS

Object Relational Data (ORD) User used by Time Series, etc

Created by: ?/ord/admin/ordinst.sql


DSSYS/DSSYS

Oracle Dynamic Services and Syndication Server

Created by: ?/ds/sql/dssys_init.sql


MDSYS/MDSYS

Oracle Spatial administrator user

Created by: ?/ord/admin/ordinst.sql


AURORA$ORB$UNAUTHENTICATED/INVALID

Used for users who do not authenticate in Aurora/ORB

Created by: ?/javavm/install/init_orb.sql called from ?/javavm/install/initjvm.sql


PERFSTAT/PERFSTAT

Oracle Statistics Package (STATSPACK) that supersedes UTLBSTAT/UTLESTAT

Created by: ?/rdbms/admin/statscre.sql

Remember to change the passwords for the SYS and SYSTEM users
immediately after installation!

Except for the user SYS, there should be no problem altering these
users to use a different default and temporary tablespace.