In memory database / Data Caching

Hi All,

Our company is about to develop a product (Web application).

Scenario / Requirement:

The application is going to be used by multiple concurrent users (approx 50 to 70). The applications basic feature is to provide search. This search will be of different entities (name, place, organization, etc.). Further these entities are interlinked.

Issue / Challenge:

So as to have better performance and lesser DB interactions we plan to store these entity objects in server RAM (in memory). And periodically update them. We are not able to finalize what approach to follow to achieve this. Some of the options we think of;

1) Asp.net Data Caching

2) In memory databases. E.g. http://www.mongodb.com/what-is-mongodb

3) some thing else.

Kindly provide us inputs on this.

Any thoughts / comments highly appreciated.

Thanks in advance