1. What is a 3-Tier Architecture?

In the world of software development, 3-tier architecture has become the backbone of modern application design. A 3-tier architecture is an architecture pattern used in applications as a specific type of client-server system. It divides the architecture into three tiers: data layer, application layer, and presentation layer. 

The 3-tier architecture refers to the logical 3-tier system rather than the physical one. It adds a “middle tier” between the client and the database. The main functions and business logic of the system are processed in the middle layer, which is the application layer.

2. The Three Tiers in a 3-Tier Architecture

2.1 Presentation Tier

The presentation tier occupies the top level of the application. It sends content to browsers in web development frameworks, such as CSS, HTML, or JavaScript, and displays information in the form of a graphical user interface (GUI), which allows users to access it directly. It communicates with other layers by putting out the results to the browser and other tiers through API calls. 

2.2 Application Tier

The application tier is also called the business logic, logic tier, or middle tier. By processing the business logic for the application, it builds a bridge between the presentation layer and the data layer to make communication faster between the presentation and data layer.

The application tier is usually coded in C#, Java, C++, Python, Ruby, etc.

2.3 Data Tier

Data-tier is composed of a persistent storage mechanism and the data access layer. It supports connecting with the database and performing insert, update, delete, and get data from the database based on our input data. 

3. Rules in the 3-Tier Architecture

1. The core rule: the presentation layer is only a shell and cannot contain any processing of BizLogic.

2. The design should be from the application layer rather than the presentation layer. The API of the application layer should implement all BizLogic on the API in an object-oriented manner.

3. Whether the data layer is a simple SqlHelper or a class with Mapping, make sure it is independent of the abstract system layer.

4. Whether you’re using COM+(EnterpriseService), Remoting, or a remote object technology like WebService, whether you’re deploying it on a server or not, you have to consider clustering multiple servers through load balancing in your design.

To sum up, when considering whether a project conforms to the application of a three-tier or multi-tier design, it is necessary to find whether it conforms to the requirements of the project.

4. What are the Advantages and Disadvantages of Using a 3-Tier Architecture?

Advantages:

• It reduces dependencies between layers, following the principles of 3-tier architecture. Therefore, as long as developers adhere to interface standards and utilize the same entity classes of the object model, it allows different developers to work on each layer. This aspect can significantly improve the development speed of the system.
• In a 3-tier architecture, each layer can be redeveloped or modernized independently, without affecting other layers. This capability shortens the time to market and reduces the cost of integrating new features into software as a service (SaaS), Cloud, and on-premise applications.
• It provides ease of maintenance, and won’t affect other modules, which dramatically reduces maintenance costs and maintenance time.
• Instead of directly accessing the data layer, the presentation layer only connects with the business logic layer, which improves data security.

Disadvantages:

• It reduces system performance. Without a hierarchical structure, businesses could go directly to the database to get the data, but now they have to go through the middle tier.
• The 3-tier architecture sometimes results in cascading changes, especially in the top-down direction. If you need to add a feature in the presentation layer in the context of what is 3-tier architecture, you may need to add code in both the business logic layer and the data access layer to ensure that the design adheres to the principles of 3-tier architecture.

5. 3-Tier Architecture Example 

Take FineReport as an example to help you better understand the 3-tier architecture. FineReport is reporting software that adopted the 3-tier architecture. 

The data layer of FineReport is responsible for data management, including data collection, ETL, building a data warehouse, etc. It supports multiple data sources and data integration. 

The application layer of FineReport is responsible for the main functions and business logic. In this part, as an enterprise reporting tool, it supports report design, report generation, and report management. 

In the presentation layer, FineReport can adaptively display reports and dashboards on PC, mobile, and TV screens because the charts in FineReport are developed by HTML5, which can be used cross-platform, adaptive to web design, and support instant updates.

For example, when you want to create a sales report based on the sales data stored in the CRM, the presentation layers send API calls to the data layer, the data layer of the FineReport runs the query and returns the results to the application layer, which formats it into a web page. The page is then sent back to the browser, where the presentation layer displays the reports on a laptop or other device.

With the 3-tier architecture, you only need to install the designer on the report designer’s computer, and then deploy the project to the server. Other users can directly access the report as long as there is a browser on the computer. 

Once the report requirements change, it is very convenient to design locally and then publish to the remote server by switching the working directory or directly edit the report files on the remote server.

In this way, for companies, it only needs to deploy the project once, and then it can be designed directly and remotely, which makes migrating reports conveniently and improves efficiency.

6. A Conclusion of the 3-Tier Architecture

A 3-tier architecture is an architectural pattern used in the client-server system. Hope you could have a clear understanding of the advantages, disadvantages, rules, and examples of 3-tier architecture after reading this article.

3-tier architecture has revolutionized the software development process by providing developers with a flexible, scalable, and maintainable framework for building modern applications. With the help of powerful reporting tools like FineReport, developers can quickly and easily create complex reports, providing users with the insights they need to make informed decisions.

FineReport provides a free personal-use edition with no limitations and supports up to two concurrent users. For enterprise users interested in pricing and product details, please contact us by clicking the button below:

Also, please feel free to make an appointment for a live demo with our product experts. We will be more clear about your needs and see how FineReport can help you and your organization transform data into value.