How many database indexes is too many?

Question

I\'m working on a project with a rather large Oracle database (although my question applies equally well to other databases). We have a web interface which allows users to

Answer 1

It is totally based on the columns which are being used in Where Clause. And as the Thumb of Rule, we must have indexes on Foreign Key Columns to avoid DEADLOCKS. AWR report should analyze periodically to understand the need of indexes.