E-Business Suite

I noticed that this question has been asked a few times but remains unanswered.

I need to understand what the difference is between DBI and BI. Why would a company implement DBI and why not? Similarly, why would a company want to implement BI and why not?

Can DBI and BI both be implemented and what would the implications of that be?

Is BI Discoverer part of DBI? Can BI Discoverer be used on top of DBI?

I need to guide my company in making the correct decision. I've read the articles on Metalink but can't get a clear picture or where DBI an BI fit into the E-business Suite environment.

Any help would be greatly appreciated!