Learn Database Concepts

Virtual Columns: Oracle 11g introduced the concept of ‘ Virtual Column ’ within a table. Virtual Columns are similar to normal table’s columns but with the following differences: They are defined by an expression. The result of evaluation of this expression becomes the value of the column. The values of the virtual column are not stored in the database. Rather, it’s computed at run-time when you query the data. You can’t update (in SET clause of update statement) the values of virtual column. These are read only values, that are computed dynamically and any attempt to modify them will result into oracle error. The syntax for defining a virtual column is: column_name [datatype] [GENERATED ALWAYS] AS [expression] [VIRTUAL] where the parameters within [ ] are optional and can be omitted. If you don’t mention the datatype, Oracle will decide it based on the result of the expression. Excepting the above points, a virtual column, exists just like any other column of a normal table and the fo...

WinSCP Config The WinSCP Config is quite simple and utilizes its “tunnel” feature. Open WinSCP and configure a saved session for the final destination host as follows: On the Session page, fill in the hostname and user name for the final destination host. Leave the password blank. Check the “Advanced options” box in the login dialog. Select the Connection –> Tunnel page. Check the “Connect through SSH tunnel” box. Fill in the Host name and user name of the intermediate host. Leave the password blank. Save the session using the button in the lower right-hand corner of the window. When you log in using the new profile, you will be prompted for two passwords. The first is for your account on the intermediate host, and the second is for your account on the final-destination host. After login, the bounce is entirely transparent and WinSCP works as if you had connected directly to the final-destination host. The connection process can be made even more transparent and secure by using publ...

WinSCP Config The WinSCP Config is quite simple and utilizes its “tunnel” feature. Open WinSCP and configure a saved session for the final destination host as follows: On the Session page, fill in the hostname and user name for the final destination host. Leave the password blank. Check the “Advanced options” box in the login dialog. Select the Connection –> Tunnel page. Check the “Connect through SSH tunnel” box. Fill in the Host name and user name of the intermediate host. Leave the password blank. Save the session using the button in the lower right-hand corner of the window. When you log in using the new profile, you will be prompted for two passwords. The first is for your account on the intermediate host, and the second is for your account on the final-destination host. After login, the bounce is entirely transparent and WinSCP works as if you had connected directly to the final-destination host. The connection process can be made even more transparent and secure by...

Below packages can usually be ignored as oracle installer thinks they are not available and are still needed while they already exists. [root@rac2 Desktop]# yum install libaio-0.3.105-2.i386.rpm Loaded plugins: refresh-packagekit, security Setting up Install Process No package libaio-0.3.105-2.i386.rpm available. Error: Nothing to do [root@rac2 Desktop]# rpm -ivh compat-libstdc++* error: File not found by glob: compat-libstdc++* [root@rac2 Desktop]# ps -ef |grep compat-libstdc++* root     11837  7817  0 19:27 pts/0    00:00:00 grep compat-libstdc++* [root@rac2 Desktop]# rpm -qa|grep compat-libstdc++* compat-libstdc++-296-2.96-144.el6.i686 compat-libstdc++-33-3.2.3-69.el6.x86_64 Reference : You can also see below notes from this link: https://www.oratoolkit.ch/knowledge/howto/installation/eeSrv-11g-R2-on-RHEL-6.0-x86_64.php Installing Oracle Software Install Oracle software without clicking through Oracle Universal Installer ( OUI ). Use instead smart  ...