As discussed earlier, there is no one best way to organize applications. Different architectures have different benefits that make them more or less appropriate for a specific project. Some projects may require only limited access so having all of your functions in one big blob makes sense.

Other projects may not need as many functional layers to separate out their apps. A very popular architecture for this are what we refer to as Single Page Applications (SPAs). With SPAs, every part of the app is its own web page that is hosted on a website platform like Google Chrome, Microsoft Edge, or Firefox.

Still other projects may benefit from an n-tier approach where each function has its own file, database table, or folder. This structure can be extended into multiple tiers depending on how much functionality needed to exist within the application.

In this article, we will talk about another common type of organization used for developing software - n-tiered architecuture.

The three tiers of an N-tier architecture

An N-tiered application is one that has separate layers to manage different functions or components. These layers are called tiers, and each tier can be added onto the app as needed.

The term “N-tier” was first used in 1994 by David Heer with his book Introduction to Computer Networks. Since then it has become very common to refer to this as an MVC (Model-View-Controller) style software design.

However, there have been other variations of N-tier architectures over time. Some people call these layered designs OOP (Object Oriented Programming) frameworks or layering patterns.

These types of N-tier systems were never widely recognized as being better than others until computer scientist Don Jorgensen coined the term microservice in 2016. Microservices are not fully understood yet, but what we do know is they are a highly effective way to organize large applications.

Microservices are also referred to as fat free services because only small pieces of code are included in each individual service. This makes changes easier to make since nothing else depends on it.

This article will talk about the differences between classic MVC styles of design and how they relate to modern day microservices.

The middle tier

As we discussed, the three tiers of an MVC application are the model, view, and controller. But what if you want to add another layer? This is where N-tier architecture comes in!

N-tier applications have a fourth (or more) layer that separates out functions. In software engineering terms, this means there are additional layers between your code and the user. These extra layers are typically referred to as the middleware or server-side technology.

The most common types of servers include PHP,.NET, Ruby, Python, Java, and so on. Almost any language can be used for creating these middleware technologies.

PHP is one of the most popular languages for developing web sites and apps due to its widespread availability and ease of use. Some people even develop their own languages to run in this space! For example, Django and Flask are two very commonly used open source frameworks that create new languages inside of it.

In this article, we will focus only on writing backend APIs using the latest version of Node.js and the JavaScript programming language. While not every developer has experience with both of these, they are extremely accessible and easy to pick up!

What is An API?

API stands for Application Programming Interface. It is a way to access some functionality within a computer program.

For instance, let’s say I have a recipe app that allows users to make recipes and then search through them.

The data access layer

Data access is one of the most important parts of any application, and this is doubly true for large applications that need to perform well. If your app does not have solid data access, or if it is poorly optimized, then your apps will not run as efficiently and quickly as possible!

Data access comes in two main forms: raw SQL queries and object oriented APIs. Both are necessary in order to achieve good performance in your app.

SQL is a very powerful way to interact with databases. However, using pure SQL can become unwieldy as the number of columns and tables increase. This is where an Object Oriented API comes into play. These types of interfaces use abstract classes and objects to create a clean interface similar to when you would write basic functions in programming.

These database interaction tools exist already, so what about creating our own? That’s just the beginning! Once we have our toolbox full of common functionality, we can start building upon them by adding features specific to whatever type of database we want to connect to.

This article will talk more about these concepts and how to implement a simple data access layer in PHP.

The business logic layer

This is an integral part of any n-tier architecture. Depending on what your website or app does, there are many ways to organize this layer.

Some people refer to it as the backend scripting language, since it allows you to create scripts that interact with external systems (for example, databases).

Other people call it the data access layer because it goes in for all of the internal database tables and fields.

And then there’s middleware, which is just like the business logic layer, but separate. It comes between your application code and the external resources it interacts with.

It is very common to use middleware when building apps that have a lot of different features or need extra security.

What isn’t so popular is using multiple instances of the same middleware class. For example, if one piece of middleware can connect to both a MySQL and SQL Server database, most developers will choose one over the other.

The presentation layer

This is probably one of the most important layers in any software project, especially when it comes to developing web applications. After all, your website or app will not run without this layer!

The reason for this is because this is where UI (user interface) components come from.

You have probably used at least some form of UI component before — something like an “Add Member” button, a login screen with buttons, or even just color scheme and style variations for websites.

These are examples of what we refer to as user interface elements or widgets. They are functions that users can use to interact with your application. For instance, adding members to an organization or logging into an account.

As you may already know, browsers and other apps use HTML and CSS to render these types of widgets. These languages are referred to as markup languages since they are made up of small pieces of text called tags along with some special characters such as quotes and brackets. Then, using a language called Cascading Style Sheets (CSS), you can combine these different styles and characteristics together to achieve your desired look and feel.

That being said, the browser/app uses its internal rendering engine to apply these tags and styles. It is then up to each individual device how to format the element.

The database

A common beginner mistake is to assume that creating a web app means using only JavaScript, HTML, and CSS as programming languages. This assumption is very common because most people who begin working with Web Development use those tools heavily.

But what most beginners don’t realize is that there are other “higher level” languages you can use in addition to these ones.

A higher level language is one that acts on or manipulates another language – like SQL. And we have a term for this type of language: a Database.

That’s why it’s called N-tier architecture!

N refers to the fact that this layer exists beyond just your application code and browser.

The service layer

In software architecture, a tier is a separation of an application into discrete components to facilitate management, maintenance, and development. With modern technology, these tiers are typically broken down into several more specific layers or structures.

These additional layers are referred to as “layers” because they separate out functions of the app in terms of what it can do, but they are not necessary physically located away from each other. For instance, with web applications, the browser (the client) connects to the internet, your computer does as well, and both have a network manager that allows them to talk to other networks and devices.

Software architectures use this analogy by saying that the browser, operating system, and program manager are all part of the same layer, but they are separated off so they can independently perform their tasks. This concept applies similarly to developing software.

In software engineering, this concept of layering is extended one step further. By adding another layer, you create something called an n-tier architecutre. An n-tiered architecture has a user interface (UI), a database, and a business logic (or sometimes referred to as a controller) layer.

The UI layer is responsible for taking input data from the users and passing it onto the next layer. The database handles storing information and the controllers take commands given by the next layer and execute them. Once everything passes through the final layer, then the output is displayed either automatically or manually.

The infrastructure layer

As mentioned before, this is typically referred to as the backend or data access layer. It handles all of your database functions- querying for information, updating records, and deleting expired entries.

There are many different open source databases you can use to build your infrastructure layer. Many of these have plugins that allow them to work with any application framework.

For example, most people use MySQL as their underlying database. So if you were building an eCommerce website then you would need a database server running MySQL. There are many free hosting sites that offer both paid and free accounts that will let you run a basic site on theirs.

Most web hosts also offer software packages that include preconfigured connectors for some of the common database servers. For example, they may give you PHP tools to connect to SQL Server, Oracle, or MSSQL instances.

By having these prebuilt connections, it saves you time from having to learn how to configure each one individually. These are usually in the form of readyto-use scripts or at least easy ways to get up and going quickly.

The best way to pick which ones to use is by doing a little research and reading reviews. Make sure to look at not only whether they work but how well they work too!

Just because someone else used the tool successfully does not mean it works well for you or your project. You want to make sure it’s stable and reliable before using it.