I am working on a social networking website which requires person-to-person connections & relationships(of different level) to be stored and retrieved in Database in efficient manner?
May I know answer to following questions:- i) Any idea which is best database (in terms of easiness and efficient queries) for these kind of projects? ii) Any idea what orkut/facebook might be use at DB side? iii) Any idea what technology should I choose for front end to give it up-to-date social-networking-site-look-and-feel?
1) Depends on your use cases and on how you plan to fetch data back.
2) It doesn't really matter because they most probably could have done it on anything and later on change as the site grew. That's because their problem #1 is not implementing the features but scaling.
3) html + css
To answer your question regarding what Facebook uses for it's DB etc. There servers run a LAMP Stack with a lot of custom compiled services running on the back-end. Check out this link for more info:
http://www.makeuseof.com/tag/facebook-work-nuts-bolts-technology-explained/
来源：https://stackoverflow.com/questions/4842276/designing-a-social-networking-website-db-and-front-end