Beyond the Monolith: Embracing Flexibility with N-Tiered Architectures

The key to any good system is it’s ability to be scalable, robust, and maintainable.

There are thousands of massive companies in the world, and as developers, we play a small cog in the advancing tech industry. FAANG (Facebook, Amazon, Apple, Netflix, and Google) appears like a field of Monoliths — intractably indivisible and uniform.

However, when you abstract away the scale, you too can understand the building blocks of massive tech stacks.

N-Tiered (Layered) Architecture is engineered to have processing, data management, and presentation functions both physically and logically separated. The different functions are hosted on different machines or clusters, ensuring these services are delivered at top capacity.

The significance of an N-Tiered system lies in its ability to provide services at the best possible rate and make the overall project easier to manage.

This is because the layers are functionally independent from one another. In this post, we’ll cover the basics of the N-Tier pattern, common Tiers, and best practices.

First, we have to understand the difference between layers and tiers, as they both play a vital role in achieving a scalable, maintainable, and efficient N-Tier architecture.

Layers represent the logical separation of concerns within an application through the internal organization of code and components, ensuring separation of concerns and high cohesion (which we will cover later).

Tiers represent the physical separation of components across different environments or servers. Tiers are concerned with the deployment and distribution of components rather than the internal organization of the code.

There are three common Layers to the N-Tier architecture: the Presentation Layer, the Business Logic Layer, and the Data Access Layer. These all have unique functions that allow them to operate independently.

Let’s transition to a metaphor for something we can all understand. Food!

Imagine a Restaurant.

The dining area and menu of our restaurant (humorously named “Byte Bistro”), where customers choose their desired dishes and interact with the staff, represent our Presentation Layer. This is the top-most level of the application that a user can interface with, translating tasks and results into something the user can understand.

The kitchen represents the Business Logic Layer. Chefs prepare the dishes according to the recipes and specific customer requests, ensuring the correct combination of ingredients and cooking techniques. By example, our Business Logic Layer processes commands, makes logical decisions and evaluations, and moves and processes data between the two surrounding layers.

Lastly, the pantry and storeroom, where ingredients are stored, organized, and fetched, represent our Data Access Layer. This is where we store information and retrieve it from a database or file system. The information is then passed back to the logic tier for processing and eventually served (no pun intended) to the user.

Some common tech stacks (frameworks and programming languages used together) used in the N-Tiered pattern are:

LAMP stack:

• Presentation Layer: HTML, CSS, JavaScript
• Business Logic Layer: PHP
• Data Access Layer: MySQL

MEAN stack:

• Presentation Layer: AngularJS
• Business Logic Layer: Node.js, Express.js
• Data Access Layer: MongoDB

Python stack:

• Presentation Layer: HTML, CSS, JavaScript
• Business Logic Layer: Python, Django or Flask
• Data Access Layer: PostgreSQL, MySQL, or SQLite

You might be thinking that this is great for a general understanding of the pattern, but what are some “best practices” when implementing an N-Tiered system? I’ve got you covered.

Along with common programming principles like documentation and readability, you also want to keep in mind some more complex ideas, such as separation of concerns, loose coupling/high cohesion, and dependency inversion.

Separation of concerns is the principle that you design components within each layer to have a clear and distinct responsibility. The more defined and specific your components, the easier it will be to keep code organized, maintainable, and easier to understand in the future.

Loose Coupling and High Cohesion is the principle that you design components with distinct metrics. Firstly, you want to design with high cohesion, meaning components within one class or module should functionally belong together and do one particular thing. Meanwhile, loose coupling implies that different classes/modules should have minimal dependency on one another. This allows the system to be easier to modify and extend individual components without affecting the rest of the system.

Lastly, Dependency Inversion is the principle of minimizing direct dependencies between layers, allowing for easier swapping of implementations or modifications without affecting other layers.

We explored the fundamental concepts of the N-Tiered pattern, highlighted its benefits and common implementations, and discussed some core principles when using N-Tier architecture.

By understanding the role of each layer and applying the best practices, you, as a developer, can also create a monolith of your own — standing tall, discrete, and exact.

👉 Thank you for taking your time to read through my article! Leave a comment below if you’d like to continue the conversation.

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