O/S level authentication in Oracle DBA

Blog Author


Published Date

30th September, 2020




  • Share this blog :


O/S level authentication

SYS> !

[dba12 dbs] $ vi initrajpar.ora

   Single quote


[dba12 dbs] $ exit

SYS> startup force  à includes shut abort & startup

[just like restart]

{not suggestible command}

SYS> sho parameter OS_authent_prefix

SYS> create user raj6x71A identified externally;

The user should have os level authentication.

SYS> grant connect, resource to raj6x 71A;

SYS> !

[dba12 ~] $ pwd


[dba12 ~] $ sqlplus

SQL > sho user raj6x 71A


Inclined to build a profession as Oracle DBA Training? Then here is the blog post on, explore Oracle DBA Training

To create password file

[db a 12 dbs] $ vi initrajpor.ora

Remote-login_password file= exclusive


[dba12 dbs] $ orapwd file = orapw $ ORACLE_SID password= diamond

[dba12 dbs] $ cd

[dba12 ~] $ exit

SYS> startup force

SYS> sho parameter remote_login



SYS> select * from v$ pwfile_users

Now SYS can grant SYSDBA privileges to any other user.

SYS> grant sysdba to usr1;

SYS> startup force

SYS> conn user 1/user1 as sysdba

User1> startup force

SQL> sho user user1


ROL =s:

SYS> select * from session _ privs;

SYS> create role pay-1;

SYS> grant create tablespsce, create user to pay-1;

SYS> grant pay-1 to suer – 1;



(views related to roles)

    Storage management      

  1. One segment can only be created in one tablespace
  2. One tablespace can have multiple segments.
  • One segment is made up of one or more extents.
  1. One extent is made up of COB.[contiguous oracle blocks]
  • One segment can have its multiple extents in the same or different data files provided these data files belongs to the same tablespace.
  • When a segment’s extents are completely filled up, ORACLE offers another extent to support the growth of the segments on its own. This is known as DSA [dynamic space allocation] which is limited the free space available in the tablespace.

  EMP Table Extents            

For an in-depth knowledge, click on below

About Author


Author Bio

TekSlate is the best online training provider in delivering world-class IT skills to individuals and corporates from all parts of the globe. We are proven experts in accumulating every need of an IT skills upgrade aspirant and have delivered excellent services. We aim to bring you all the essentials to learn and master new technologies in the market with our articles, blogs, and videos. Build your career success with us, enhancing most in-demand skills .

Related Blogs

Write For Us