Creating Oracle Linked Server in SQL Server

I wrote multiple articles on heterogeneous linked server which helped user to connect to Sybase , SQL Server & MySQL RDBMS platforms. However I missed creating Oracle linked server , many users responded to write an article on this so I decided to complete it. As you know when you create a heterogeneous linked server you need proper driver of the destination RDBMS. I have split this into two sections a.) Installing Oracle Driver and configuring tnsnames.ora file b.) Creating Oracle linked server in SQL Server