title: How to query effectively in Oracle SQL before inserting any data
body: <p>My scenario is like I have thousands of row in a table. And the table has 8 columns. I would like to check whether the exact same row exists in the table. My requirement I shouldn't insert the same row in the table twice. Obviously, to do so I have to compare every row before any new insertion. I don't have much SQL expertise, so I don't know what is the best way to so that I can gain maximum efficiency. Please advice me.         </p>