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The Oracle SQL Connect Command - Oracle

Oracle is one of the top relational databases in the world and has been used by Fortune 500 companies such as Exxon Mobil, Wal-mart, General Electric and many others. In this tutorial, we will show you six "must know" Oracle SQL commands.

  1. Six Must Know Oracle Commands
  2. The Oracle SQL Connect Command
  3. The Oracle SQL Create User/Grant Command
  4. The Create Table, Insert, and Select Oracle SQL Commands
By: Codex-M
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March 16, 2011

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Second Command:

Now that you have started Oracle in Ubuntu, the next thing is to login as SYSTEM. The user “SYSTEM” has database administration privileges that have been created during the installation of Oracle in Ubuntu. You should remember the password you assign for “SYSTEM”. To use the “connect” command and login as SYSTEM, type the following into the SQL-plus prompt (after starting Oracle using the startup command):

SQL> connect system
Enter password:

Once you see “connected” you are connected as “system” to Oracle. The following are some common problems relating to the CONNECT command in Oracle:

First Problem:

ORA-01034: ORACLE not available
ORA-27121: unable to determine size of shared memory segment
Linux Error: 13: Permission denied

Second Problem:

ORA-27140: attach to post/wait facility failed


In Linux terminal:

1.) Login as root:

codex-m@codex-m-desktop:~$ sudo -s -H
[sudo] password for codex-m:

2.) Go to root directory:

root@codex-m-desktop:/home/codex-m# cd /

3.) Go to /usr/lib and list the files/directories under it

root@codex-m-desktop:/# cd usr/lib
root@codex-m-desktop:/usr/lib# ls -l -a

 Look for “oracle” and make sure it has the following permission and owners:

drwxr-xr-x 3 root root 4096 2011-03-11 01:21 oracle

4.) Now cd (change directory) to oracle:

root@codex-m-desktop:/usr/lib# cd oracle

5.) Assign the following owners and groups to the xe folder:

root@codex-m-desktop:/usr/lib/oracle# chown oracle:dba xe

6.) Go to the bin directory:

root@codex-m-desktop:/usr/lib/oracle# cd xe/app/oracle/product/10.2.0/server/bin

7.) Finally change the file permission for Oracle to 6751 (chmod 6751):

root@codex-m-desktop:/usr/lib/oracle/xe/app/oracle/product/10.2.0/server/bin# chmod 6751 oracle

8.) Confirm the you have the correct owner and file permissions for the Oracle executable here (ls -l -a):

root@codex-m-desktop:/usr/lib/oracle/xe/app/oracle/product/10.2.0/server/bin# ls -l -a

This the correct file permission and owner:

-rwsr-s--x  1 oracle dba 74016776 2006-02-25 04:43 oracle

>>> More Oracle Articles          >>> More By Codex-M

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