In order to fully cater for our customer’s business needs, we sometimes opt to implement application development using windows technology. In this technology, we normally deliver to our customer a set of complete empty database and a packaged CD of user interface application which is used to run a setup of the application into the users’ computers.
Using window technology, we do develop applications which run in the mult-user environment. The physical architecture of these applications is either two tiers or three tiers. In two tiers application, the database is deployed in a separate physical server from users’ computers, whereby the data for the entire system remains accessible and sharable among all users. In most cases we use two tiers architecture for those applications which run in the local area network (LAN) only because of availability of unlimited bandwidth there.
Like two tiers architecture, the three tiers architecture is composed of client application and database server, but it has one more tier that comes between client application and database. The tier is commonly known as application server. The presence of this third tier enhances the security of the entire system as it completely buries the database from being directly accessed by client application. For the systems which run in the wide area network (WAN), it significantly lowers bandwidth consumption and therefore increases the possibility of running fast in the slow networks.