3 Tier Architecture vs 2 Tier Architecture

Question

What are the examples where we really need 3 Tier Architecture ? Can Most of the Application which are using 3 Tier Architecture be done using 2 Tier Architecture ?

Answer 1

Some databases expose a rest interface to the outside world, for instance NoSQL databases CouchDB and RavenDB. That means that the Javascript running in your browser can call the database without a middle tier.

See for example: http://www.infoq.com/news/2010/06/couchdb

" Well behaved HTTP/REST interface and API Clean and simple two tier applications (html+javascript in the browser + couch+javascript as server)"

Oracle has a web server inside, you can use stored procs that also expose a rest interface to the outside world. So the JavaScript in your browser can also call the Oracle database without a middle tier.

Do you always need a middle tier when all you want is to get some data from the database? I question that need.

(TTT formerly known as Tuinstoel)