i want to know what thing makes a application complex? is it only the database or some other things. what if Facebook has only thousand users then would it be so complex as it is now.
If I have n rows in a database, and I want to compare every row against each other, how many loops (or processes) would I need to do. Is it n2? (so if I have 30,000 rows then it would be 900,000,000) ...