This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
Priyakant, Many databases automatically create an index on the primary key (likely id in your example.)
There would be no point in creating an index on all the columns in the table - automatically or manually. The reason is that such an index would be just as large as the source table. Which means it would take just as long to scan as the table.