what is a presentation tier architecture

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 application data is stored and managed.

The chief benefit of three-tier architecture is that because each tier runs on its own infrastructure, each tier can be developed simultaneously by a separate development team. And can be updated or scaled as needed without impacting the other tiers.

For decades three-tier architecture was the prevailing architecture for client-server applications. Today, most three-tier applications are targets for modernization that uses cloud-native technologies such as containers and microservices and for migration to the cloud.

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Presentation tier

The presentation tier is the user interface and communication layer of the application, where the end user interacts with the application. Its main purpose is to display information to and collect information from the user. This top-level tier can run on a web browser, as desktop application, or a graphical user interface (GUI), for example. Web presentation tiers are developed by using HTML, CSS, and JavaScript. Desktop applications can be written in various languages depending on the platform.

Application tier

The application tier, also known as the logic tier or middle tier, is the heart of the application. In this tier, information that is collected in the presentation tier is processed - sometimes against other information in the data tier - using business logic, a specific set of business rules. The application tier can also add, delete, or modify data in the data tier. 

The application tier is typically developed by using Python, Java, Perl, PHP or Ruby, and communicates with the data tier by using  API  calls. 

The data tier, sometimes called database tier, data access tier or back-end, is where the information that is processed by the application is stored and managed. This can be a  relational database management system  such as  PostgreSQL , MySQL, MariaDB, Oracle, Db2, Informix or Microsoft SQL Server, or in a  NoSQL  Database server such as Cassandra,  CouchDB , or  MongoDB . 

In a three-tier application, all communication goes through the application tier. The presentation tier and the data tier cannot communicate directly with one another.

Tier versus layer

In discussions of three-tier architecture,  layer  is often used interchangeably – and mistakenly – for  tier , as in 'presentation layer' or 'business logic layer'. 

They aren't the same. A 'layer' refers to a functional division of the software, but a 'tier' refers to a functional division of the software that runs on infrastructure separate from the other divisions. The Contacts app on your phone, for example, is a  three - layer  application, but a  single-tier  application, because all three layers run on your phone.

The difference is important because layers can't offer the same benefits as tiers.

Again, the chief benefit of three-tier architecture is its logical and physical separation of functionality. Each tier can run on a separate operating system and server platform - for example, web server, application server, database server - that best fits its functional requirements. And each tier runs on at least one dedicated server hardware or virtual server, so the services of each tier can be customized and optimized without impacting the other tiers. 

Other benefits (compared to single- or two-tier architecture) include:

• Faster development : Because each tier can be developed simultaneously by different teams, an organization can bring the application to market faster. And programmers can use the latest and best languages and tools for each tier.
• Improved scalability : Any tier can be scaled independently of the others as needed.
• Improved reliability : An outage in one tier is less likely to impact the availability or performance of the other tiers.
• Improved security : Because the presentation tier and data tier can't communicate directly, a well-designed application tier can function as an internal firewall, preventing SQL injections and other malicious exploits.

In web development, the tiers have different names but perform similar functions:

• The web server  is the presentation tier and provides the user interface. This is usually a web page or website, such as an ecommerce site where the user adds products to the shopping cart, adds payment details or creates an account. The content can be static or dynamic, and is developed using HTML, CSS, and JavaScript.
• The application server  corresponds to the middle tier, housing the business logic that is used to process user inputs. To continue the ecommerce example, this is the tier that queries the inventory database to return product availability, or adds details to a customer's profile. This layer often developed using Python, Ruby, or PHP and runs a framework such as Django, Rails, Symphony, or ASP.NET.
• The database server  is the data or backend tier of a web application. It runs on database management software, such as MySQL, Oracle, DB2, or PostgreSQL.

While three-tier architecture is easily the most widely adopted multitier application architecture, there are others that you might encounter in your work or your research.

Two-tier architecture 

Two-tier architecture is the original client-server architecture, consisting of a presentation tier and a data tier; the business logic lives in the presentation tier, the data tier or both. In two-tier architecture the presentation tier - and therefore the end user - has direct access to the data tier, and the business logic is often limited. A simple contact management application, where users can enter and retrieve contact data, is an example of a two-tier application. 

N-tier architecture

N-tier architecture - also called or multitier architecture - refers to  any  application architecture with more than one tier. But applications with more than three layers are rare because extra layers offer few benefits and can make the application slower, harder to manage and more expensive to run. As a result, n-tier architecture and multitier architecture are usually synonyms for three-tier architecture.

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What is a 3-tier application architecture? Definition and Examples

Michael Chiaramonte

May 13, 2024

In software development, it’s very common to see applications built with a specific architectural paradigm in mind. One of the most prevalent patterns seen in modern software architecture is the 3-tier (or three-tier) architecture. This model structures an application into three distinct tiers: presentation (user interface), logic(business logic), and data (data storage).

The fundamental advantage of 3-tier architecture lies in the clear separation of concerns. Each tier operates independently, allowing developers to focus on specific aspects of the application without affecting other layers. This enhances maintainability, as updates or changes can be made to a single tier with minimal impact on the others. 3-tier applications are also highly scalable since each tier can be scaled horizontally or vertically to handle increased demand as usage grows.

This post delves into the fundamentals of 3-tier applications. In it, We’ll cover:

• The concept of 3-tier architecture: What it is and why it’s important.
• The role of each tier: Detailed explanations of the presentation, application, and data tiers.
• How the three tiers interact: The flow of data and communication within a 3-tier application.
• Real-world examples: Practical illustrations of how 3-tier architecture is used.
• Benefits of this approach: Advantages for developers, architects, and end-users.

With the agenda set, let’s precisely define the three tiers of the architecture in greater detail.

What is a 3-tier application architecture?

A 3-tier application is a model that divides an application into three interconnected layers:

• Presentation Tier: The user interface where the end-user interacts with the system (e.g., a web browser or a mobile app).
• Logic Tier: The middle tier of the architecture, also known as the logic tier, handles the application’s core processing, business rules, and calculations.
• Data Tier: Manages the storage, retrieval, and manipulation of the application’s data, typically utilizing a database.

This layered separation offers several key advantages that we will explore in more depth later in the post, but first, let’s examine them at a high level. 

First, it allows for scalability since each tier can be scaled independently to meet changing performance demands. Second, 3-tier applications are highly flexible; tiers can be updated or replaced with newer technologies without disrupting the entire application. Third, maintainability is enhanced, as modifications to one tier often have minimal or no effect on other tiers. Finally, a layered architecture allows for improved security, as multiple layers of protection can be implemented to safeguard sensitive data and business logic.

How does a 3-tier application architecture work?

The fundamental principle of a 3-tier application is the flow of information and requests through the tiers. Depending on the technologies you use, each layer has mechanisms that allow each part of the architecture to communicate with the other adjacent layer. Here’s a simplified breakdown:

• User Interaction: The user interacts with the presentation tier (e.g., enters data into a web form or clicks a button on a mobile app).
• Request Processing: The presentation tier sends the user’s request to the application tier.
• Business Logic: The logic tier executes the relevant business logic, processes the data, and potentially interacts with the data tier to retrieve or store information.
• Data Access: If necessary, the application tier communicates with the data tier to access the database, either reading data to be processed or writing data for storage.
• Response: The logic tier formulates a response based on the processed data and business rules and packages it into the expected format the presentation tier requires.
• Display: The presentation tier receives the response from the application tier and displays the information to the user (e.g., updates a webpage or renders a result in a mobile app).

The important part is that the user never directly interacts with the logic or data tiers. All user interactions with the application occur through the presentation tier. The same goes for each adjacent layer in the 3-tier application. For example, the presentation layer communicates with the logic layer but never directly with the data layer. To understand how this compares to other n-tier architectural styles, let’s take a look at a brief comparison.

1-tier vs 2-tier vs 3-tier applications

While 3-tier architecture is a popular and well-structured approach, it’s not the only way to build applications. As time has passed, architecture has evolved to contain more layers. Some approaches are still used, especially in legacy applications. Here’s a brief comparison of 1-tier, 2-tier, and 3-tier architectures:

• All application components (presentation, logic, and data) reside within a single program or unit.
• Simpler to develop initially, particularly for small-scale applications.
• It becomes increasingly difficult to maintain and scale as complexity grows.
• Divides the application into two parts: the client (presentation/graphical user interface) and a server, which typically handles both logic and data.
• Offers some modularity and improved scalability compared to 1-tier.
• Can still face scalability challenges for complex systems, as the server tier combines business logic and data access, potentially creating a bottleneck.
• Separates the application into presentation, application (business logic), and data tiers.
• Provides the greatest level of separation, promoting scalability, maintainability, and flexibility.
• Typically requires more development overhead compared to simpler architectures.

The choice of architecture and physical computing tiers that your architecture uses depends on your application’s size, complexity, and scalability requirements. Using a multi-tier architecture tends to be the most popular approach, whether client-server architecture or 3-tier. That being said, monolithic applications still exist and have their place.

The logical tiers of a 3-tier application architecture

The three tiers at the heart of a 3-tier architecture are not simply physical divisions; they also represent a separation in technologies used. Let’s look at each tier in closer detail:

1. Presentation tier

• Focus: User interaction and display of information.
• Role: This is the interface that users see and interact with. It gathers input, formats and sanitizes data, and displays the results returned from the other tiers.
• Web Development: HTML, CSS/SCSS/Sass, TypeScript/JavaScript, front-end frameworks (React, Angular, Vue.js), a web server.
• Mobile Development: Platform-specific technologies (Swift, Kotlin, etc.).
• Desktop Applications: Platform-specific UI libraries or third-party cross-platform development tools.

2. Logic tier

• Focus: Core functionality and business logic.
• Role: This tier is the brain of the application. It processes data, implements business rules and logic, further validates input, and coordinates interactions between the presentation and data tiers.
• Programming Languages: Java, Python, JavaScript, C#, Ruby, etc.
• Web Frameworks: Spring, Django, Ruby on Rails, etc.
• App Server/Web Server

3. Data tier

• Focus: Persistent storage and management of data.
• Role: This tier reliably stores the application’s data and handles all access requests. It protects data integrity and ensures consistency.
• Database servers: Relational (MySQL, PostgreSQL, Microsoft SQL Server) or NoSQL (MongoDB, Cassandra).
• Database Management Systems: Provide tools to create, access, and manage data.
• Storage providers (AWS S3, Azure Blobs, etc)

Separating concerns among these tiers enhances the software’s modularity. This makes updating, maintaining, or replacing specific components easier without breaking the whole application.

3-tier application examples

Whether a desktop or web app, 3-tier applications come in many forms across almost every industry. Here are a few relatable examples of how a 3-tier architecture can be used and a breakdown of what each layer would be responsible for within the system.

E-commerce websites

• Presentation Layer: The online storefront with product catalogs, shopping carts, and checkout interfaces.
• Logic Layer: Handles searching, order processing, inventory management, interfacing with 3rd-party payment vendors, and business rules like discounts and promotions.
• Data Layer: Stores product information, customer data, order history, and financial transactions in a database.

Content management systems (CMS)

• Presentation Layer: The administrative dashboard and the public-facing website.
• LogicLayer: Manages content creation, editing, publishing, and the website’s structure and logic based on rules, permissions, schedules, and configuration
• Data Layer: Stores articles, media files, user information, and website settings.

Customer relationship management (CRM) systems

• Presentation Layer: Web or mobile interfaces for sales and support teams.
• Logic Layer: Processes customer data, tracks interactions, manages sales pipelines, and automates marketing campaigns.
• Data Layer: Maintains a database server with data for customers, contacts, sales opportunities, and support cases.

Online booking platforms (e.g., hotels, flights, appointments)

• Presentation Layer: Search features, promotional materials, and reservation interfaces.
• Logic Layer: Handles availability checks, real-time pricing, booking logic, and payment processing to 3rd-party payment vendors.
• Data Layer: Stores schedules, reservations, inventory information, and customer details.

Of course, these are just a few simplified examples of a 3-tier architecture in action. Many of the applications we use daily will use a 3-tier architecture (or potentially more tiers for a modern web-based application), so finding further examples is generally not much of a stretch. The examples above demonstrate how application functionality can be divided into one of the three tiers.

Benefits of a 3-tier app architecture

One of the benefits of the 3-tier architecture is it’s usually quite apparent why using it would be advantageous over other options, such as a two-tier architecture. However, let’s briefly summarize the advantages and benefits for developers, architects, and end-users who will build or utilize the 3-tier architecture pattern.

Scalability

Each tier can be independently scaled to handle increased load or demand. For example, you can add more servers to the logic tier to improve processing capabilities without affecting the user experience or add more database servers to improve query performance.

Maintainability

Changes to one tier often have minimal impact on the others, making it easier to modify, update, or debug specific application components. As long as contracts between the layers (such as API definitions or data mappings) don’t change, developers can benefit from shorter development cycles and reduced risk.

Flexibility

You can upgrade or replace technologies within individual tiers without overhauling the entire system. This allows for greater adaptability as requirements evolve. For example, if the technology you are using within your data tier does not support a particular feature you need, you can replace that technology while leaving the application and presentation layers untouched, as long as contracts between the layers don’t change (just as above).

Improved Security

Multiple layers of security can be implemented across tiers. This also isolates the sensitive data layer behind the logic layer, reducing potential attack surfaces. For instance, you can have the logic layer enforce field-level validation on a form and sanitize the data that comes through. This allows for two checks on the data, preventing security issues such as SQL injection and others listed in the OWASP Top 10 .

Reusability 

Components within the logic tier can sometimes be reused in other applications, promoting efficiency and code standardization. For example, a mobile application, a web application, and a desktop application may all leverage the same application layer and corresponding data layer. If the logic layer is exposed externally through a REST API or similar technology, it also opens up the possibility of leveraging this functionality for third-party developers to take advantage of the API and the underlying functionality.

Developer specialization 

Teams can specialize in specific tiers (e.g., front-end, back-end, database), optimizing their skills and improving development efficiency. Although many developers these days focus on full-stack development, larger organizations still divide teams based on frontend and backend technologies. Implementing a 3-tier architecture fits well with this paradigm of splitting up responsibilities.

The benefits listed above cover multiple angles, from staffing and infrastructure to security and beyond. The potential upside of leveraging 3-tier architectures is wide-reaching and broadly applicable. It leaves no question as to why 3-tier architectures have become the standard for almost all modern applications. That being said, many times, the current implementation of an application can be improved, and if an application is currently undergoing modernization, how do you ensure that it will meet your target and future state architecture roadmap? This is where vFunction can swoop in and help.

How vFunction can help with modernizing 3-tier applications

vFunction offers powerful tools to aid architects and developers in streamlining the modernization of 3-tier applications and addressing their potential weaknesses. Here’s how it empowers architects and developers:

Architectural observability

vFunction provides deep insights into your application’s architecture, tracking critical events like new dependencies, domain changes, and increasing complexity over time. This visibility allows you to pinpoint areas for proactive optimization and the creation of modular business domains as you continue to work on the application.

Resiliency enhancement

vFunction helps you identify potential architectural risks that might affect application resiliency . It generates prioritized recommendations and actions to strengthen your architecture and minimize the impact of downtime.

Targeted optimization

vFunction’s analysis pinpoints technical debt and bottlenecks within your applications. This lets you focus modernization efforts where they matter most, promoting engineering velocity, scalability, and performance.

Informed decision-making

vFunction’s comprehensive architectural views support data-driven architecture decisions on refactoring, migrating components to the cloud, or optimizing within the existing structure.

By empowering you with deep architectural insights and actionable recommendations, vFunction accelerates modernization architectural improvement processes, ensuring your 3-tier applications remain adaptable, resilient, and performant as they evolve.

In this post, we looked at how a 3-tier architecture can provide a proven foundation for building scalable, maintainable, and secure applications. By understanding its core principles, the role of each tier, and its real-world applications, developers can leverage this pattern to tackle complex software projects more effectively.

Key takeaways from our deep dive into 3-tier applications include:

• Separation of Concerns: A 3-tier architecture promotes clear modularity, making applications easier to develop, update, and debug.
• Scalability: Its ability to scale tiers independently allows applications to adapt to changing performance demands.
• Flexibility: Technologies within tiers can be updated or replaced without disrupting the entire application.
• Security: The layered design enables enhanced security measures and isolation of sensitive data.

As applications grow in complexity, tools like vFunction become invaluable. vFunction’s focus on architectural observability, analysis, and proactive recommendations means that architects and developers can modernize their applications strategically, with complete visibility of how every change affects the overall system architecture. This allows them to optimize performance, enhance resiliency, and make informed decisions about their architecture’s evolution.

If you’re looking to build modern and resilient software, considering the 3-tier architecture or (a topic for another post) microservices as a starting point, combined with tools like vFunction for managing long-term evolution, can be a recipe for success. Contact us today to learn more about how vFunction can help you modernize and build better software with architectural observability.

Principal Architect

Starting from a young age, Michael has loved building things in code and working with tech. His career has spanned many industries, platforms, and projects over the 20+ years he has worked as a software engineer, architect, and leader.

Other Related Resources

What is application modernization? The ultimate guide.

What is legacy modernization?

Monolith to microservices: all you need to know

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3-tier application architecture

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What is a 3-tier application?

A 3-tier application architecture is a modular client-server architecture that consists of a presentation tier, an application tier and a data tier. The data tier stores information, the application tier handles logic and the presentation tier is a graphical user interface ( GUI ) that communicates with the other two tiers. The three tiers are logical, not physical, and may or may not run on the same physical server.

The logical tiers of a 3-tier application architecture

Presentation tier : This tier, which is built with HTML5, cascading style sheets ( CSS ) and JavaScript , is deployed to a computing device through a web browser or a web-based application. The presentation tier communicates with the other tiers through application program interface ( API ) calls.

Application tier : The application tier, which may also be referred to as the logic tier, is written in a programming language such as Java and contains the business logic that supports the application's core functions. The underlying application tier can either be hosted on distributed servers in the cloud or on a dedicated in-house server, depending on how much processing power the application requires.

Data tier : The data tier consists of a database and a program for managing read and write access to a database. This tier may also be referred to as the storage tier and can be hosted on-premises or in the cloud. Popular database systems for managing read/write access include MySQL , PostgreSQL, Microsoft SQL Server and MongoDB .

Benefits of a 3-tier app architecture

The benefits of using a 3-tier architecture include improved horizontal scalability, performance and availability. With three tiers, each part can be developed concurrently by a different team of programmers coding in different languages from the other tier developers. Because the programming for a tier can be changed or relocated without affecting the other tiers, the 3-tier model makes it easier for an enterprise or software packager to continually evolve an application as new needs and opportunities arise. Existing applications or critical parts can be permanently or temporarily retained and encapsulated within the new tier of which it becomes a component.

3-tier application programs may also be referred to as n-tier programs. In this context, the letter n stands for "a number of tiers."

Continue Reading About 3-tier application architecture

• A quick rundown of 3 layered architecture design styles
• Enterprise design: Is three-tiered architecture still useful?
• What is 2nd and 3rd tier Middleware?
• Adopting a 4-tier architecture for mobile solutions
• Web app architectures overview

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Software Architecture: One-Tier, Two-Tier, Three Tier, N Tier

In this Software Architecture tutorial, we will learn the following

Software Architecture

A “tier” can also be referred to as a “layer”.

#1. Presentation Layer

In simple words, it is to view the application.

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#2. Application Layer

#3. data layer.

In simple words, it is to share and retrieve the data.

Must Read: Manual Testing Complete Tutorial

Types of Software Architecture:

#1. one tier architecture:.

One Tier application AKA Standalone application

Must Read: Most Popular Software Testing Interview Questions

#2. Two-Tier Architecture:

The client system handles both Presentation and Application layers and the Server system handles the Database layer. It is also known as a client-server application. The communication takes place between the Client and the Server. The client system sends the request to the server system and the Server system processes the request and sends back the data to the Client System

#3. Three-Tier Architecture:

1. Presentation layer (Client Tier) 2. Application layer (Business Tier) 2. Database layer (Data Tier)

Note: Another layer is the N-Tier application. N-Tier application AKA Distributed application. It is similar to the three-tier architecture but the number of application servers is increased and represented in individual tiers in order to distribute the business logic so that the logic will be distributed.

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Three-tier architecture overview

The three-tier architecture is the most popular implementation of a multi-tier architecture and consists of a single presentation tier, logic tier, and data tier. The following illustration shows an example of a simple, generic three-tier application.

Architectural pattern for a three-tier application

There are many great online resources where you can learn more about the general three-tier architecture pattern. This whitepaper focuses on a specific implementation pattern for this architecture using Amazon API Gateway and AWS Lambda.

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Posted on Apr 3

Understanding Layers, Tiers, and N-Tier Architecture in Application Development

In the realm of application development, the architecture of an application significantly impacts its performance, scalability, and ease of maintenance. Developers often talk about "layers" and "tiers" within an application's architecture, terms that are crucial but sometimes misunderstood.

In this article, we will clarify these concepts and delve into the N-tier architecture, focusing on its 3-tier and 4-tier models.

Layers vs. Tiers : What's the Difference?

Although "layers" and "tiers" are often used interchangeably, they refer to different aspects of application architecture:

• Layers are virtual separations within an application that organize its different parts, such as the presentation layer (UI) , the business logic layer , and the data access layer .

These layers exist within the application's code structure and are a logical way to separate responsibilities and functionalities.

• Tiers , on the other hand, refer to the physical distribution of an application's components across different servers or platforms. This physical separation is crucial for an application's scalability, security, and performance. When components are deployed on separate servers and still communicate effectively, they form what is known as a tiered architecture.

Introducing N-Tier Architecture:

N-tier architecture is a scalable and flexible way to structure applications, where "N" represents the number of tiers involved. This architecture divides the application into multiple tiers, each responsible for specific aspects of the application's functionality.

3-Tier Architecture (The Most Common Model):

The 3-tier architecture is a widely adopted model in application development, consisting of the following tiers:

Presentation Tier Tier: This is the user interface (UI) layer, where users interact with the application. It's built using technologies like HTML , CSS , JavaScript , and frameworks like React or Angular .

Application Tier : The core of the application, this layer contains business rules and logic. It acts as an intermediary between the presentation and data access layers, ensuring that user inputs are processed and validated. Technologies used include server-side languages like Java , C# , Python , and frameworks like .NET , Spring , or Django .

Data Tier : This layer is responsible for managing the application's data. This layer handles communication with databases or other storage mechanisms, providing CRUD (Create, Read, Update, Delete) operations. It uses technologies like JDBC, Entity Framework, or ORM.

4-Tier Architecture:

This additional layer abstracts the business logic's external communication, making the system more modular and enabling services to be reused across different parts of the application or even across different applications. It's particularly useful in microservices and service-oriented architectures.

In more complex applications, a 4-tier architecture may be employed, which adds an additional tier:

Delivery Tier : This tier focuses on caching and delivering front-end assets to the client, often through a Content Delivery Network ( CDN ).

The CDN enhances the application's performance and user experience by storing and serving static content from locations closest to the user.

Benefits of N-Tier Architecture:

Scalability : Separating an application into tiers allows for easier scaling of each component independently.

Security : It becomes easier to implement security measures, as each tier can have its own security protocols.

Maintainability : Updates and bug fixes can be carried out more efficiently since changes in one tier do not necessarily affect others.

Efficiency : The development process is streamlined, as developers can focus on specific aspects of the application within each tier.

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Understanding 3-Tier Web Architecture: A Beginner’s Guide

The most common architecture and deployment approach for ensuring a project’s robustness, redundancy, and resilience is a 3-tier architecture. In this article, I will dissect the three tiers and outline their typical construction.

Presentation Tier

The presentation tier is the user interface that is commonly displayed on a web browser as a web page or web site. It is primarily but not exclusively used to see and alter information or data.

How to build the presentation tier? 

In web development the presentation tier is commonly built with HTML, CSS, and  JS. Some examples of technologies used to build the presentation tier would be popular javascript frameworks such as react, angular and vuejs.

Application Tier

The application tier (also known as logic tier) is in charge of the core functionality of a web application. It is in charge of the business logic of the application, and processing the information collected from the presentation tier. 

How to build the application tier?

This layer is often developed using python, PHP, C# or Java using frameworks like Django, Laravel or ASP.net. There are many other languages and frameworks that can be used to build this layer but these are just a few.

The data tier houses the database and is independent of the application tier. The application tier processes the information and stores it in the data tier

How to create the data tier?

The data tier is often managed and created using database tools such as mysql, MongoDB, Oracle or postgres.

• November 10, 2023
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The most common architecture and deployment approach for ensuring a project’s robustness, redundancy, and resilience is a 3-tier architecture. In this article, I will dissect

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What is Three-Tier Architecture? A Comprehensive Guide

By Happy Sharer

Introduction

The three-tier architecture is a software development model that divides an application into three distinct layers – the presentation layer, the application layer, and the data layer. This architecture is used to simplify complex systems and provide scalability, security, and cost savings for businesses. In this article, we’ll explore the definition of three-tier architecture and its benefits, as well as provide an overview of system design and implementation.

A Guide to Understanding Three-Tier Architecture

Before we dive into the benefits of three-tier architecture, let’s take a closer look at what it is and how it works.

What is a Three-Tier Architecture?

Three-tier architecture is a type of software system architecture that divides an application into three distinct layers – the presentation layer, the application layer, and the data layer. Each layer is responsible for different aspects of the application, so that all the components are separated and can be modified independently without affecting the other parts of the system.

Components and Structures of a Three-Tier System

The presentation layer of a three-tier system is responsible for interacting with the user. It is the interface between the user and the system, and includes all the graphical elements of the application, such as menus, buttons, and forms. The application layer handles the logic of the system, including processing user requests, retrieving data from the database, and performing calculations. The data layer stores the data and provides access to it for the other layers. It is typically implemented using a database management system (DBMS).

Types of Three-Tier Architectures

There are two main types of three-tier architectures: client-server and n-tier. In a client-server architecture, the presentation layer and the application layer are located on the server, while the data layer is located on the client. In an n-tier architecture, all three layers are distributed across multiple servers. This allows for greater scalability and flexibility, as each layer can be scaled independently.

Exploring the Benefits of a Three-Tier Architecture

Now that you understand the basics of three-tier architecture, let’s take a look at some of the benefits it offers.

Scalability

One of the major advantages of three-tier architecture is its scalability. Each layer can be scaled independently, allowing the system to grow or shrink depending on the needs of the business. This makes it ideal for businesses that need to adjust their applications quickly and easily.

Another benefit of three-tier architecture is the ability to isolate sensitive data from the rest of the system. By separating the data layer from the other two layers, it is more secure and less vulnerable to attack. Additionally, each component can be secured separately, allowing for greater control over the system.

Flexibility

Using a three-tier architecture also provides increased flexibility. Since each layer can be modified independently, changes can be made quickly and easily without affecting the other layers. This makes it easier to make adjustments to the system without having to rebuild it from scratch.

Cost Savings

Finally, three-tier architecture can help businesses save money. By separating the components, businesses can avoid costly hardware upgrades and instead focus on optimizing their existing infrastructure. Additionally, since each layer can be scaled independently, businesses can save money by only scaling the layers they need.

An Overview of Three-Tier System Design

Now that you understand the benefits of three-tier architecture, let’s take a look at how it is designed.

Logical Layers

The logical layers of a three-tier system include the presentation layer, the application layer, and the data layer. These layers are responsible for different functions within the system and are isolated from each other to ensure that changes to one layer do not affect the others.

Physical Layers

The physical layers of a three-tier system include the hardware, operating system, and network layers. The hardware layer consists of the physical components of the system, such as the servers, storage devices, and other devices. The operating system layer is responsible for managing the system resources, such as memory and processor usage. Finally, the network layer is responsible for connecting the various components of the system.

Application Layers

The application layers of a three-tier system include the web server, application server, and database server. The web server is responsible for presenting the user interface and providing access to the application layer. The application server is responsible for processing user requests, retrieving data from the database, and performing calculations. Finally, the database server is responsible for storing and managing the data.

How Three-Tier Architecture Can Help Your Business

Now that you understand the basics of three-tier architecture, let’s take a look at how it can help improve the performance, reliability, and productivity of your business.

Improved Performance

By separating the components of the system, three-tier architecture can help improve the performance of the system. By isolating the components, the system can run more efficiently, reducing response times and improving overall performance.

Enhanced Reliability

The isolation of components also helps to enhance the reliability of the system. If one component fails, the other components will still be able to function, ensuring that the system remains available even in the event of a failure.

Increased Productivity

Finally, three-tier architecture can help increase the productivity of your business. By separating the components, changes can be made quickly and easily, allowing for faster development and deployment of new features and updates.

Implementing Three-Tier Architecture for Maximum Efficiency

Now that you understand the benefits of three-tier architecture, let’s take a look at how you can implement it in your business for maximum efficiency.

Establishing a Database Layer

The first step in implementing a three-tier system is to establish a database layer. This layer will store the data and provide access to it for the other layers. You will need to choose a database system that meets the requirements of your application and configure it properly.

Connecting the Application Layer

Once the database layer is established, you can begin connecting the application layer. This layer will be responsible for processing user requests, retrieving data from the database, and performing calculations. You will need to design the application to meet the needs of your system, as well as configure it properly.

Securing the Network Layer

Finally, you will need to secure the network layer. This layer is responsible for connecting the various components of the system and ensuring that the data is transmitted securely. You will need to configure the network properly, as well as install any necessary security measures.

In conclusion, three-tier architecture is a software development model that divides an application into three distinct layers – the presentation layer, the application layer, and the data layer. This architecture offers many benefits, such as scalability, security, flexibility, and cost savings. It can also help improve the performance, reliability, and productivity of your business. To get the most out of it, you will need to properly configure the database, application, and network layers.

Three-tier architecture is a software development model that divides an application into three distinct layers – the presentation layer, the application layer, and the data layer. This architecture offers many benefits, such as scalability, security, flexibility, and cost savings. To get the most out of it, you will need to properly configure the database, application, and network layers.

Final Thoughts

Three-tier architecture can provide businesses with many benefits, such as scalability, security, flexibility, and cost savings. By understanding the components and structures of a three-tier system, as well as the benefits it provides, businesses can leverage this architecture to improve the performance, reliability, and productivity of their applications.

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Hi, I'm Happy Sharer and I love sharing interesting and useful knowledge with others. I have a passion for learning and enjoy explaining complex concepts in a simple way.

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A Guide To 3-Tier Architecture

A well-structured and organized solution is crucial for maintainability and scalability in software development. The 3-Tier architecture clarifies concerns, allowing developers to manage the application logic, data access, and presentation layers separately. In this article, we will explore the benefits of this architecture and learn how to implement it in a Visual Studio solution using C#. 

Different Architectures

There are many types of architectures you can use for your applications. You just have to find the one that suits your needs. I like the 3-tier architecture. It’s small, simple, and easy to create. But in some cases, I might change it because of my needs.

There are 9 known architectures we use these days in C#:

• Monolithic architecture
• Microservices architecture
• 3-tier architecture
• Model-View-Controller (MVC) architecture
• Model-View-Presenter (MVP) architecture
• Model-View-ViewModel (MVVM) architecture
• Event-Driven architecture
• Service-Oriented Architecture (SOA)
• Client-Server architecture

I am not going to explain them all. It will become a very large page. But the top 3 popular architectures are:

• Microservices architecture A way to break down a large and complex application into smaller, independent services that are connected. They communicate with each other through APIs. This architecture is becoming popular with bigger projects. You can maintain and deploy the smaller projects more easily.
• 3-tier architecture This type of architecture separates an application into three logical components: the presentation layer, the application layer, and the data layer. This separation of concerns provides better scalability, maintainability, and ease of development.
• Model-View-Controller (MVC) architecture  Well-known if you have created web applications and/or  APIs  with C#. It is a design that separates the application logic from the user interface. The Model component represents the data and the business logic, the View component displays the data, and the Controller component handles user input and updates the Model. This separation of concerns provides a more organized and maintainable codebase.

This tutorial explains the 3-tier architecture mainly because we use this one the most.

The 3-Tier Architecture

This architecture separates the application into three logical components. These three layers help to maintain the code and separation of concern. But for me, it has a different reason I use this architecture: reusability. 

Especially at a time when you might want to create a Windows, macOS, Android, Linux, and iOS app that does the same thing. Do you create the same class over and over again? No, you create a class library with the logic and reference that library in all the projects that need the logic. If something changes in the class library, all other projects get updated.

Three Different Layers

Each layer has its own responsibility but only talks to one other layer. The presentation layer only talks to the application layer and the application layer only talks to the data layer. That means that if you want to show a list of movies, for example, you need to ask the application layer which will ask the data layer. The application layer will send the information of the data layer to the presentation layer. The presentation layer never talks to the data layer directly.

The Data Layer

The first layer I am discussing is the data layer. Maybe the name already tells you what this layer is about: Data. It could be data from a database or a file. Generally speaking, we use this layer to transport data from and to a data source.

This layer does not contain any form of logic. It just sends or retrieves data from the data source. Nothing special. Logic is placed in the application layer.

If you have multiple data sources you need to manage, you can create multiple data layers and bring them together in the application by using dependency injection.

The data layer is a layer that is disappearing a bit. Before we had ORMs, like  Entity Framework , we had to write a lot of code to retrieve and send data from and to a database. With Entity Framework, we don’t need that anymore. That is the reason the logic for the database is moving to the application layer.

The Application Layer

This layer is the beating heart for all your logic. Here you combine logic with the data from the data layer. This layer is responsible for calculations and decisions before sending the data to your presentation layer.

The application layer is often called the business layer. This is a small heritage from the time we had the DLL (data layer library) and the BLL (business layer library). In my projects, I usually call it the business.

For example, the presentation layer requests a list of movies, ordered by title. The application layer will retrieve all the movies from the data layer and sort them by title.

This layer does nothing with the data source directly. The reason is simple: The application layer should never know what kind of data source you use. If you implement dependency injection, the data source can change. Even the whole data layer can change (except for the interface). But the application layer should always be working without changing it.

You can have multiple application layers. I created a logger once. A simple logger that stores messages in a file. But later I needed a logger that stored the messages in a database. I didn’t want two loggers in the single class library representing my application layer. So I created a second application layer for the logger.

It’s usually this layer we  unit test  because it contains the most important code of our application.

The Presentation Layer

And last but not least; the presentation layer. This layer is what a user sees. It could be a console application, WinForms, or an API. It’s the one that gives output that a user or a client application can work with. This layer is also referred to as the top-most layer in this architecture.

It is responsible for presenting the data from the application layer in a user-friendly way. Examples of user-friendly are web pages, WinForms, and mobile apps.

A console application or a WinForms application has a clear GUI. You can click on stuff and it works. An API doesn’t have that. But it does expose JSON (or XML if you want). An API is considered a front-end application.

Conclusion On A Guide to 3-Tier Architecture

The 3-tier architecture is the most used because it’s easy to understand and implement. I encourage you to use this if you just start or create a small project. If you have a really, really small project; make your life easier, and don’t use layers.

The idea behind these layers is to separate data, logic, and application. I think the names are a bit confusing and most people think the application layer is the front end, but that’s the presentation layer. And that is why I call the application layer the business layer.

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1. What is a 3-Tier Architecture?

2.1 presentation tier, 2.2 application tier, 2.3 data tier, 3. rules in the 3-tier architecture, 4. what are the advantages and disadvantages of using a 3-tier architecture, 5. 3-tier architecture example , 6. a conclusion of the 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

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. 

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.

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. 

• 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.

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.

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.

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.

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Three-Tier Client Server Architecture in Distributed System

The Three-Tier Client-Server Architecture divides systems into presentation, application, and data layers, enhancing scalability, maintainability, and efficiency. By separating concerns, this model optimizes resource management and allows for independent scaling and updates, making it a popular choice for complex distributed systems .

Important Topics for Three-Tier Client Server Architecture in Distributed System

What are Distributed Systems?

What is three-tier client server architecture in distributed systems, importance of three-tier client server architecture in distributed systems, components of three-tier client server architecture in distributed systems, three-tier application in web development, benefits of three-tier client-server architecture, disadvantages of three-tier client server architecture, faqs on three tier client server architecture.

Distributed systems are networks of independent computers that work together to achieve a common goal. They share resources and communicate over a network to provide services or perform tasks as if they were a single cohesive system. Examples include cloud computing platforms, online banking systems, and social media networks.

The Three-Tier Client-Server Architecture in distributed systems is a design model that separates applications into three distinct layers:

• Presentation Tier : The user interface layer, where interactions occur. It handles data display and user input.
• Application Tier : The business logic layer, which processes user requests, performs computations, and makes decisions. It acts as a mediator between the presentation and data tiers.
• Data Tier : The storage layer, is responsible for managing and storing data. It handles database operations and data retrieval.

This separation helps improve scalability, manageability, and flexibility by isolating each layer’s responsibilities.

The Three-Tier Client-Server Architecture is crucial in distributed systems for several reasons:

• Scalability : Each tier can be scaled independently. For example, the application tier can be scaled to handle increased business logic load without affecting the presentation or data tiers.
• Maintainability : With a clear separation of concerns, developers can update or modify one tier without disrupting others, simplifying maintenance and reducing the risk of system-wide issues.
• Flexibility : Changes in one tier (e.g., updating the user interface) can be implemented without impacting the underlying business logic or data management, allowing for easier upgrades and customizations.
• Performance : Distributing tasks across different tiers can optimize resource use and performance. For instance, caching strategies can be implemented at the application tier to enhance response times.
• Security : Each tier can have distinct security measures. For example, sensitive data can be securely managed at the data tier, while the presentation tier focuses on user interaction.

The Three-Tier Client-Server Architecture is a layered approach to building distributed systems, with each tier serving distinct roles. Here’s a detailed explanation of each component:

1. Presentation Tier (Client Tier)

The Presentation Tier is responsible for the user interface and user interaction. It serves as the front-end of the application, where users input data and view results.

• User Interface (UI): Includes web browsers, mobile apps, or desktop applications that users interact with. It displays data and collects user inputs.
• User Interaction Logic: Handles how user inputs are processed and communicated to the Application Tier. This can involve form validation, data formatting, and sending requests to the server.
• Display data from the Application Tier to the user.
• Collect user inputs and forward them to the Application Tier.
• Provide a user-friendly interface and manage user interactions.

2. Application Tier (Business Logic Tier)

The Application Tier is where the core business logic resides. It processes user requests, performs calculations, enforces business rules, and interacts with the Data Tier to retrieve or store data.

• Business Logic: Implements the rules and processes specific to the application, such as order processing, authentication, or data validation.
• Application Server: Hosts the business logic and handles communication between the Presentation and Data Tiers. Examples include web servers or application servers like Apache Tomcat, Microsoft IIS, or JBoss.
• Process and interpret data received from the Presentation Tier.
• Execute business logic and apply rules.
• Communicate with the Data Tier to retrieve or store information.
• Send processed data back to the Presentation Tier for user display.

3. Data Tier (Database Tier)

The Data Tier is responsible for data management and storage. It handles all database operations, including data retrieval, updates, and management.

• Database Management System (DBMS): Software like MySQL, Oracle, or Microsoft SQL Server that manages data storage and retrieval.
• Database: The actual repository where data is stored, organized in tables or other structures.
• Store and manage data securely and efficiently.
• Handle queries and transactions initiated by the Application Tier.
• Ensure data integrity, consistency, and availability.
• Provide backup and recovery mechanisms to protect data.

Interactions Among Tiers

• Client Request: The user interacts with the Presentation Tier, which sends a request to the Application Tier.
• Business Processing: The Application Tier processes the request using its business logic and may interact with the Data Tier to retrieve or update data.
• Data Retrieval/Update: The Data Tier handles data operations and sends the results back to the Application Tier.
• Response to Client: The Application Tier processes the results and sends the response back to the Presentation Tier for display to the user.

This tiered approach helps manage complexity by separating responsibilities, allowing for easier maintenance, scalability, and flexibility in distributed systems

Web application will have the same tiers as the three architectures but only difference is that they are with different names.

• Web Server: Web server is an presentation tier of an three-tier architecture which servers as an presentation tier or UI (User Interface) tier. This content can be static or dynamic based on there requirement such as an e-commerce site where users can add products to their shopping cart, enter payment details, or create an account.
• Application Server: Application tier is an middle tier which consists the full logical that is required for the business which will process the user inputs and so on. It will performs the logic’s like queries the inventory database to return product availability or adds details to a customer’s profile.
• Database server: This is back-end tier of an web application it consists all the data so this tier mostly there will be data base such as MySQL, Oracle, DB2 or PostgreSQL.

Below are the benefits of three-tier client-server architecture in distributed systems:

• Vertical Scaling: Each tier can be scaled independently. For instance, you can add more application servers or database servers to handle increased load without affecting the presentation tier.
• Horizontal Scaling: You can distribute the load across multiple servers for each tier, enhancing the system’s ability to handle large volumes of requests.
• Modular Design: The separation of concerns allows developers to make changes or updates to one tier without affecting others. For example, updating the user interface or business logic can be done independently.
• Easier Debugging: Isolating issues becomes easier as each tier has its own distinct responsibilities.
• Technology Independence: Different technologies and platforms can be used for each tier. For example, the presentation layer might use a web framework, while the application layer could use a different programming language or framework.
• Enhanced Adaptability: Changes in business logic or data storage mechanisms can be implemented without affecting the user interface or other parts of the system.
• Optimized Resource Use: Performance can be optimized at each tier. For instance, caching mechanisms can be applied at the application tier to reduce database load.
• Load Balancing : Distributing workload across multiple servers at each tier can enhance overall system performance and responsiveness.

Below are the challenges of three-tier client-server architecture in distributed systems:

• System Design : Designing and implementing a three-tier architecture can be complex due to the need to manage interactions and data flow between tiers.
• Integration Issues: Ensuring seamless integration between tiers may require additional development and testing effort.
• Network Latency : Communication between tiers, especially when they are distributed across different servers or locations, can introduce latency and affect performance.
• Increased Resource Usage: Multiple layers may increase resource consumption, such as network bandwidth and server processing power.
• Configuration Management: Managing configurations and deployments for multiple tiers can be challenging, particularly in distributed environments.
• Version Compatibility: Ensuring compatibility between different versions of each tier (e.g., updated business logic or database schema) requires careful coordination.
• Infrastructure Costs: Operating and maintaining separate servers or services for each tier can increase infrastructure and operational costs.
• Development Costs: The initial development and ongoing maintenance can be more expensive due to the complexity of managing and updating multiple tiers.

Below are the main faqs in three-tier client server architecture in distributed systems:

Q1: How do you handle network latency and performance issues in a Three-Tier Architecture?

Implement caching , load balancing , and optimize data transmission to mitigate latency and enhance performance.

Q2: What are the best practices for ensuring data consistency across distributed tiers?

Use transactional integrity, synchronization mechanisms, and consistency models to maintain data consistency.

Q3: How do you handle version compatibility between different tiers in a Three-Tier Architecture?

Employ API versioning, backward compatibility, and rolling deployments to mana ge version compatibility.

Q4: What are the security considerations for each tier in a Three-Tier Architecture, and how do you implement them?

Secure each tier with appropriate authentication, encryption, access controls, and regular security audits.

Q5: How do you approach scaling each tier independently, and what are the challenges involved?

Scale each tier horizontally or vertically as needed, using load balancers and monitoring tools to manage complexity and resource allocation

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N-tier architecture style

An N-tier architecture divides an application into logical layers and physical tiers .

Layers are a way to separate responsibilities and manage dependencies. Each layer has a specific responsibility. A higher layer can use services in a lower layer, but not the other way around.

Tiers are physically separated, running on separate machines. Contractually, the tier can have their communication models be strict or relaxed. In the strict model, a request must go through adjacent tiers, one by one, and can't skip any tier in between. For example, from the web application firewall to the web tier, then to middle tier 1, and so on. In contrast, in the relaxed approach, the request may skip some tiers if it's necessary. The strict approach has more latency and overhead, and the relaxed approach has more couplings and subsequently it's more difficult to change. A system can use a hybrid approach: having both relaxed and strict tiers where necessary.

A tier can call to another tier directly, or use Asynchronous messaging patterns through a message queue. Although each layer might be hosted in its own tier, that's not required. Several layers might be hosted on the same tier. Physically separating the tiers improves scalability and resiliency, but also adds latency from the additional network communication.

A traditional three-tier application has a presentation tier, a middle tier, and a database tier. The middle tier is optional. More complex applications can have more than three tiers. The diagram above shows an application with two middle tiers, encapsulating different areas of functionality.

An N-tier application can have a closed layer architecture or an open layer architecture :

• In a closed layer architecture, a layer can only call the next layer immediately down.
• In an open layer architecture, a layer can call any of the layers below it.

A closed layer architecture limits the dependencies between layers. However, it might create unnecessary network traffic, if one layer simply passes requests along to the next layer.

When to use this architecture

N-tier architectures are typically implemented as infrastructure-as-service (IaaS) applications, with each tier running on a separate set of VMs. However, an N-tier application doesn't need to be pure IaaS. Often, it's advantageous to use managed services for some parts of the architecture, particularly caching, messaging, and data storage.

Consider an N-tier architecture for:

• Simple web applications.
• A good starting point when architectural requirements are not clear yet.
• Migrating an on-premises application to Azure with minimal refactoring.
• Unified development of on-premises and cloud applications.

N-tier architectures are very common in traditional on-premises applications, so it's a natural fit for migrating existing workloads to Azure.

• Portability between cloud and on-premises, and between cloud platforms.
• Less learning curve for most developers.
• Relatively low cost by not rearchitecting the solution
• Natural evolution from the traditional application model.
• Open to heterogeneous environment (Windows/Linux)
• It's easy to end up with a middle tier that just does CRUD operations on the database, adding extra latency without doing any useful work.
• Monolithic design prevents independent deployment of features.
• Managing an IaaS application is more work than an application that uses only managed services.
• It can be difficult to manage network security in a large system.
• User and data flows typically span across multiple tiers, adding complexity to concerns like testing and observability.

Best practices

• Use autoscaling to handle changes in load. See Autoscaling best practices .
• Use asynchronous messaging to decouple tiers.
• Cache semistatic data. See Caching best practices .
• Configure the database tier for high availability, using a solution such as SQL Server Always On availability groups .
• Place a web application firewall (WAF) between the front end and the Internet.
• Place each tier in its own subnet, and use subnets as a security boundary.
• Restrict access to the data tier, by allowing requests only from the middle tier(s).

N-tier architecture on virtual machines

This section describes a recommended N-tier architecture running on VMs.

Each tier consists of two or more VMs, placed in an availability set or virtual machine scale set. Multiple VMs provide resiliency in case one VM fails. Load balancers are used to distribute requests across the VMs in a tier. A tier can be scaled horizontally by adding more VMs to the pool.

Each tier is also placed inside its own subnet, meaning their internal IP addresses fall within the same address range. That makes it easy to apply network security group rules and route tables to individual tiers.

The web and business tiers are stateless. Any VM can handle any request for that tier. The data tier should consist of a replicated database. For Windows, we recommend SQL Server, using Always On availability groups for high availability. For Linux, choose a database that supports replication, such as Apache Cassandra.

Network security groups restrict access to each tier. For example, the database tier only allows access from the business tier.

The layer labeled "Business Tier" in our reference diagram is a moniker to the business logic tier. Likewise, we also call the presentation tier the "Web Tier." In our example, this is a web application, though multi-tier architectures can be used for other topologies as well (like desktop apps). Name your tiers what works best for your team to communicate the intent of that logical and/or physical tier in your application - you could even express that naming in resources you choose to represent that tier (e.g. vmss-appName-business-layer).

Additional considerations

N-tier architectures are not restricted to three tiers. For more complex applications, it is common to have more tiers. In that case, consider using layer-7 routing to route requests to a particular tier.

Tiers are the boundary of scalability, reliability, and security. Consider having separate tiers for services with different requirements in those areas.

Use virtual machine scale sets for autoscaling .

Look for places in the architecture where you can use a managed service without significant refactoring. In particular, look at caching, messaging, storage, and databases.

For higher security, place a network DMZ in front of the application. The DMZ includes network virtual appliances (NVAs) that implement security functionality such as firewalls and packet inspection. For more information, see Network DMZ reference architecture .

For high availability, place two or more NVAs in an availability set, with an external load balancer to distribute Internet requests across the instances. For more information, see Deploy highly available network virtual appliances .

Do not allow direct RDP or SSH access to VMs that are running application code. Instead, operators should log into a jumpbox, also called a bastion host. This is a VM on the network that administrators use to connect to the other VMs. The jumpbox has a network security group that allows RDP or SSH only from approved public IP addresses.

You can extend the Azure virtual network to your on-premises network using a site-to-site virtual private network (VPN) or Azure ExpressRoute. For more information, see Hybrid network reference architecture .

If your organization uses Active Directory to manage identity, you may want to extend your Active Directory environment to the Azure VNet. For more information, see Identity management reference architecture .

If you need higher availability than the Azure SLA for VMs provides, replicate the application across two regions and use Azure Traffic Manager for failover. For more information, see Run Windows VMs in multiple regions or Run Linux VMs in multiple regions .

Related Resources

• N-tier application with Apache Cassandra
• [Windows N-tier application on Azure with SQL Server][n-tier-windows-SQL]
• Microsoft Learn module: Tour the N-tier architecture style
• Azure Bastion
• More information on messaging in an N-tier architecture style on Azure

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Presentation layer in 3-tier architecture

My question is about various ways of implementing presentation layer in 3-tier architectures

When we talk about a 3-tier web application, it is assumed that the presentation layer is browser-oriented, and hence communicates with logic tier through HTTP protocol

I'd like to know, how presentation layer is going to communicate with logic tier, in case if the presentation layer is going to be a standalone application with its own GUI, rather than browser-based

For example, Java servlets get HTTP requests from our browser, but what about if I want to design a specific desktop application to communicate with servlets ? How my app is going to communicate with logic tier ? Which protocol is used ?

• client-server
• server-side-scripting

I guess you're misunderstanding the problems. You can say in this case the presentation layer is splitted in 2 small layers:

• Files that handle the view (JSP, Facelets, etc).
• Files that control the interaction between user and the view (Servlets, @Controller from Spring MVC, @ManagedBean from JSF, etc).

Apart from these, you can have your business logic layer (usually Service classes) and your data access layer (DAOs or whatever you feel better to call them).

If you put this in the perspective of creating GUI desktop applications, your presentation will have a similar structure:

• Classes that handle the view
• Controller classes that handle the interaction between the user and the view.

In this scenario, it usually happens that these classes are the same , but note that they are for presentation purpose and should relate with your business logic layer.

what about if I want to design a specific desktop application to communicate with servlets?

You probably mean about a client application that consumes Web Services. The Web Services (consumed by XML, JSON or plain text) could be part of a services layer that should be consumed in the business logic layer or in the presentation layer of the application, depending on what the web service returns. Still, I would find better consuming the web service layer from the business logic layer and let the presentation layer to handle its purpose: presentation logic only .

To show an example:

From comments:

Still it's unclear how business logic layer of my application is going to communicate with web service layer.

Posting a very simple skeleton sample from a Web Application Project that will consume a Web Service.

Servlet class (adapted from StackOverflow Servlet wiki ) (part of presentation)

PersonBL class (part of Business Logic Layer)

Now, posting the skeleton of the Web Service:

PersonPort class (the implementor of the Web Service)

PersonWSBL class (business logic layer in Web Service)

PersonDAO class (data access layer)

As you can notice, there's no magic in communicating the presentation with the business logic layer. Of course, this skeleton can be enhanced by using other set of technologies, but it just to illustrate the main idea.

Note: The skeleton of the Web Service was adapted from here Creating a Simple Web Service and Client with JAX-WS .

• Thanks for reply. I guess I need the ways of communication between presentation and business logic layers in your scheme above. How is that accomplished ? –  mangusta Commented Jun 10, 2013 at 23:00
• @mangusta that depends on your application design. You can consider this scenario as two applications: the first one that acts as the presentation application that will have the presentation layer and its own business logic layer (GUI, Web Application, Mobile application, it doesn't really matter as long as its purpose is presentation). Then, from your business logic layer of this app you will communicate to a web service application. Note that communication between presentation and business logic layer will depend on the technology you choose. –  Luiggi Mendoza Commented Jun 10, 2013 at 23:04
• Ok, I see. Still it's unclear how business logic layer of my application is going to communicate with web service layer. You mean that, even though if we're going to use a desktop application, we will communicate with a server part through HTTP ? –  mangusta Commented Jun 10, 2013 at 23:08
• @mangusta answer updated showing an skeleton of the proposed example. –  Luiggi Mendoza Commented Jun 10, 2013 at 23:32
• : ) so you assume that servlet is part of application's presentation layer, although it's a bit misleading because servlet is located on a server, not user machine : ) –  mangusta Commented Jun 11, 2013 at 6:44

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3 Tier Architecture in DBMS with Diagram and Their Examples

Hello Friends! Today, we will explain all possible stuff about 3 Tier architecture in DBMS with diagram and their examples with ease. This is unique content over the Internet; so at the end, you will completely learn about 3-Tier DBMS Architecture without any hassle.

What is 3-Tier DBMS Architecture?

Moreover, it is enabled with distributed computing that is allowing the database to be accessed from several locations. Therefore, the 3-tier architecture is making ensure the better organization, adaptability, and performance in database systems that help to preferred choice for complex and evolving applications.

3-Tier DBMS Architecture Tutorial Headlines:

Let’s get started, 3 tier architecture in dbms.

3-tier DBMS (Database Management System) architecture is a design approach that divides the database system into three interconnected tiers, each serving a specific purpose. These tiers are:

Also Read: What is Database Server? Types, Examples, Functions, & Working!

Diagram of 3 tier dbms architecture, presentation layer:, application layer (business logic):, data layer:, 3-layer architecture of dbms.

The three-level architecture in database management system (DBMS) consists of the following levels: external, conceptual, and internal. Each level serves a specific purpose in managing and accessing data.

External Level:

Users interact with the data at this level, and the data is fetched from the database with the help of mapping between the conceptual and internal levels.

Conceptual Level:

Internal level:.

Also known as the physical level, the internal level describes how the data is actually stored in the storage devices and is responsible for allocating space to the data.

Database Schema in 3-Tier Architecture

In 3-tier DBMS architecture, the database schema refers to the organization and structure of the database, specifically divided into three tiers or layers: presentation, application, and data.

Also Read: Advantages and Disadvantages of NoSQL Database

Data Layer: In this layer, database schema defines the structure of the actual database tables, relationships between them, constraints, and other data-related aspects. It includes entities, attributes, primary and foreign keys, ensuring data integrity and consistency.

Data Independence in 3-Tier DBMS Architecture

Also read: 25+ advantages and disadvantages of dbms, logical data independence:.

Logical data independence refers to the ability to change the logical structure of the database schema without affecting the application programs or the user interface.

Physical Data Independence:

Physical data independence refers to the ability to change the physical storage and access mechanisms without impacting the application programs or the logical schema.

Three-Tier DBMS Architecture Examples

Examples of three-tier architecture are prevalent in various software applications and systems. Here are some examples:

Enterprise Resource Planning (ERP) Systems: ERP systems often employ three-tier architecture. The presentation tier offers the user interface for interacting with the system, the application tier keeps managing the business logic and workflow processes; and the data tier manages the storage and retrieval of enterprise data.

This architecture enables scalability, resilience, and efficient resource utilization in cloud environments.

Difference between 2-Tier and 3-Tier Architecture

Here are the five differences between two-tier and three-tier database architecture, including:

Advantages of 3-Tier Architecture

Modularity and scalability.

The separation of concerns into three distinct tiers (presentation, application, and data) allows for modular development. Each tier can be developed and maintained independently, promoting scalability as components can be added or upgraded without affecting the entire system.

Easy Maintenance and Updates

Improved security.

Security measures can be utilised at each tier as independently. Access control, authentication, and encryption can be implemented at the presentation, application, and data tiers that help to enhance the overall security of the system.

Enhanced Performance

The modular structure allows for performance optimizations at each tier. For instance, caching mechanisms can be implemented in the application tier to reduce redundant database queries, improving overall system performance.

Support for Multiple Platforms

Disadvantages of 3-tier architecture.

There are some common drawbacks associated with the 3-tier architecture, as following them:

Increased Complexity

Managing three separate tiers can increase the complexity of the system. Coordinating communication and ensuring proper data flow between tiers may require additional effort.

Latency and Performance Issues

Lack of scalability.

Some crucial argue that the 3-tier architecture lacks scalability; especially in the respect of modern requirements for elasticity and rapid scaling. This criticism suggests that the architecture was developed in an era where the idea of rapid scaling did not broadly exist, potentially limiting its suitability for highly scalable and dynamic applications.

Maintenance Challenges

While the modular structure makes individual components easy to maintain, coordinating updates across multiple tiers can be challenging. Changes in one tier may necessitate corresponding modifications in other tiers to maintain compatibility.

FAQs (Frequently Asked Questions)

What are the components of 3 tier architecture, how does the 3-tier architecture differ from other architectures in dbms.

The 3-tier architecture differs from other architectures by getting to separation the application logic from the data and the user interface that are providing the added security, scalability, and flexibility as compared to two-tier architectures.

Is 3-tier architecture suitable for all types of applications?

While 3-tier architecture is widely used, its suitability depends on the specific requirements of the application. It is particularly beneficial for complex and scalable applications with diverse user interfaces.

When is the 3-tier architecture in DBMS used?

Now, we can hope that you have been fully educated about 3 Tier architecture in DBMS with diagram and their examples with ease. If this post is useful for you, then please share it along with your friends, family members or relatives over social media platforms like as Facebook, Instagram, Linked In, Twitter, and more.

Also Read: What is Database? Types, Examples, and Uses!!

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