Advantages and Disadvantages of 3-Tier Architecture in Web Development
A 3-Tier Architecture (3TA) is traditionally used when building web applications. It makes a logical separation between the presentation layer, the business logic layer, and the database layer. The main advantage of 3 tier system is that all business logic can be defined once within the business layer and then shared by any number of components within the presentation layer. Any changes to business rules can therefore be made in one place and be instantly available throughout the whole application. It is possible to change the contents of any one of tiers (layers) without having to make corresponding changes in any of the others Enables parallel development of the different tiers of the application. Complex application rules easy to implement in application server. Easy to implement changes Fewer JavaScript, thus simpler to the client Superior performance for medium to high volume environments Some of the disadvantages are; There is more processing on the web server, It does not interact with the WMS server directly. More complex structure More difficult to setup and maintain The physical separation of application servers containing business logic functions and database servers containing databases may moderately affect performance.
Advantages
1.Improved Scalability: Due to the distributed deployment of application servers, scalability of the system is enhanced since a separate connection from each client is not required whereas connections from few application servers are sufficient.
2.Enhanced Re-usage: A similar logic can be sustained in many clients or applications.
3.Improved Data Integrity: Data corruption through client applications can be eliminated as the data passed in the middle tier for database updations ensures its validity.
4.Enhanced Security: Through the implementation of several layers, enhances the data security on a service-by-service basis. As clients do not interact with the database directly, it provides less risk and confliction with unauthorized data.
5.Reduced Distribution: The layered architecture enables to update only the application servers, not all distributed clients in case of a modification in the business logic.
6.Redundant Sever Availability: mission-critical applications seek the use of superfluous application servers and database servers as its possible to create an application which will recover the system from network or server failures, with redundant servers.
7.Hidden Database Structure: The actual structure of the database often remains hidden from requesters enabling any change of the database to be transparent.
Disadvantages
1.Complexity of Communication: Usually more effort should be enforced when creating 3-tier applications as the communication points are increased
2.Fewer Tools: Additional effort is required due to increase of performance whereas the 2-tier model can handle the particular function using an automated tool.