As previously stated, a tier is the total of all physical components. The three layers can be classified as the Data Tier, the Business Tier, and the Presentation Tier. The data tier is the server that holds all of the application's data. Database tables, XML files, and other techniques of storing application data are all found under the Data layer. The business logic or services that allow users to perform specific tasks within the application are in the business tier. These services interact with the data using functions called queries or reports. The presentation layer is made up of all of the code that controls how the data is displayed on the screen. This includes HTML pages, ASP.NET web forms, and JSP scripts.
When building an application, it is important to separate the different components so that each one can be maintained and updated independently. This allows for new technologies or improvements to be implemented in one part of the system without affecting another part of the system. For example, if you were to update the HTML or CSS on a webpage but forgot to update the corresponding line of code, the page would still appear fine but would no longer be compatible with any future changes to either the HTML or CSS.
In addition to separating different components, it is also important to separate functionality between tiers. This prevents any one piece of code from becoming too large.
The three-tier architecture is a well-established software application architecture that organizes applications into three logical and physical computing tiers: the presentation tier, or user interface; the application tier, where data is processed; and the data tier, where the data associated with the application is stored and managed.
The three-tier architecture has become the standard way for organizations to structure their software systems. It provides separate layers of protection between different parts of your system, including the user interface, database, and business logic.
In addition, the three-tier architecture reduces dependency between components by keeping them in separate locations. This makes it easier to update or replace any one component without affecting other parts of the system.
Finally, the three-tier architecture is flexible enough to be applied to a wide variety of applications. You may have noticed this architecture being used in many popular web applications, such as Facebook and Google Docs.
It should also be noted that some authors use the term "three layer architecture" to describe an architecture that consists of a presentation layer, an application layer, and a data storage layer. While this terminology is widely used, it is not correct. The three-tier architecture requires only two layers: presentation and application. The third layer of data storage can be either a remote server or a local hard drive.
There are two aspects to two-tier architecture: 1.1. 1. Client Program (Client Tier) 2. Informational database (Data Tier) The display and application levels are handled by the client system, while the database layer is handled by the server system. It's also referred to as a "client-server application." The client and the server communicate with one another. Typically, the client sends requests to the server which then processes the requests and returns results back to the client.
Two-tier architecture has become the de facto standard for building web applications. By separating the display logic from the data storage mechanism, you can change how the data is displayed or stored without having to rewrite the client code. The term "thin client" is often used to describe an application that uses a two-tiered architecture.
Two-tier architecture is useful because it allows you to replace or update the information in your database without affecting the behavior of the application. For example, if the company that built your website updated their informational database with new categories or reduced the number of products they were selling, two-tier architecture would allow them to do this without needing to notify you or your users about any changes. Would be impossible to do with a single-tier architecture.
Two-tier architecture should not be confused with three-tier architecture, which adds a third tier called a "middleware" layer. Two-tier architecture refers to the client-server model, whereas three-tier architecture refers to the inclusion of a middleware layer.