=====Oracle Default User in Oracle 12c erkennen=====
**12c**


Seit Oracle 12c kann über die VIEW DBA_USERS geprüft werden, welche Oracle Schemas von Oracle selber beim Anlegen der DB für Features in der DB erzeugt wurden.


Aus der Doku:
<code>

ORACLE_MAINTAINED VARCHAR2(1)
	  	
Denotes whether the user was created, and is maintained, by Oracle-supplied scripts (such as catalog.sql or catproc.sql). A user for which this column has the value Y must not be changed in any way except by running an Oracle-supplied script.

</code>


Beispiel:

<code sql>

select count(*)
      , oracle_maintained 
  from dba_users 
 group by rollup (oracle_maintained)
/

    COUNT(*) ORA
------------ ---
          12 N
          39 Y

          51
</code>



====Quellen====

Oracle:
  * https://docs.oracle.com/database/121/REFRN/GUID-309FCCB2-2E8D-4371-9FC5-7F3B10E2A8C0.htm#REFRN23302

Web:

  * https://martincarstenbach.wordpress.com/2013/07/17/dba_users-oracle_maintained-in-12c/