Architecture of a Database System, Explained | Expedition Co

A Complete Guide to Database Architecture Types

Data is one of the most integral parts of the modern world. If you think about it, all apps, websites, and systems revolve around the ability to process and store information.

A big part of how applications access data efficiently is through a database. Put simply, a database is nothing more than a system for storing and classifying data. When designed and built well, a database can be crucial in ensuring software runs smoothly.

One of the key considerations here is the architecture of DBMS(database management systems). In this article, we’ll discuss database architecture types, the pros and cons of each, and provide examples of use cases.

What is Database Architecture?

The architecture of a database system (or DB architecture) describes how a database system interacts with your application. It tells you, for example, how data flows from a database to a web browser.

Most database architectures follow a client-server model. Here, the database sits on a centralized server, which then distributes data to multiple client machines that are connected to it. However, decentralized databases, such as those used in blockchains, will not always follow this setup.

Now, many confuse database architecture with models. While they might sound similar, they are very different concepts.

Models describe how the data itself is represented in the database. This, in turn, impacts how that data is stored and its relation to other data. For example, the simple hierarchical model allows data to have one-to-one and one-to-many relationships. In contrast, the network model facilitates complex, many-to-many connections. However, the most popular model in modern databases is the relational model, which stores data in tables.

On the other hand, architecture is how the hardware components of a database ecosystem are arranged and connected. For example, if a relational database architecture is one-tier, the client and database are all located in one machine.

The Three Types of Database Architecture

There are three database architecture types based on the number of tiers or levels between the client (software) and the database. So what is a database architecture tier? Let’s look at each in detail.

One Tier

This is one of the simplest database architecture types. Here, the client and database server are all located on one machine. So, for example, if you have a web page saved on your computer that retrieves data from a local database, that’s a one-tier architecture.

You can view one tier as a “zero tier” architecture. Database communications are often quick and direct since it’s a local connection. But, of course, that also means that the database can only serve one client – the user of that computer.

So, why would you want a one-tier architecture? Well, this structure is only used during development and testing. It allows programmers to create database functions quickly without worrying about network lag. Network administrators and system operators also use this architecture if they want to work with the database directly.

The lack of security and the inability to service multiple clients make one-tier architectures unsuitable for production.


The two-tier architecture makes a major improvement over one-tier by separating the database to its own server. This allows it to service multiple client machines, or what’s called a presentation layer.

In this architecture, most of the application programs and logic are run on each client machine. The server side is only responsible for processing queries. Clients communicate with the database server via access APIs like ODBC (Open Database Connectivity) and JDBC (Java Database Connectivity).

One danger of this is security vulnerabilities. Because clients connect to a database directly, it’s easier for hackers to access.

Thus, two-tier architectures are mostly used in private networks. For example, staff in the marketing department can use the CRM software installed on their workstations (clients) to retrieve and process data from an on-premise database (the server).


Three-tier is one of the most widely used types of architecture diagrams. That’s because it offers the best in scale and speed.

A three-tier architecture is similar to a two-tier, except an additional layer is sandwiched between the client machine and the database server. This is called the application layer, and it’s responsible for the bulk of the application logic and data management.

One of the biggest advantages of the three-tier architecture is security. Since users cannot connect to the database server directly, it’s better protected from malicious users and hackers. Three-tier architecture also runs faster than two-tier at scale since the application layer can handle multiple users much better.

Three-tier is the premier choice for websites and apps with millions of concurrent users. Software-as-a-service (SaaS) apps, for example, run on three-tier systems.

One of the few drawbacks of three-tier architectures is that they’re more complex to develop and maintain. But with the added performance and security they give, it more than makes up for it.

Consult with the Experts at Expedition

Your data is crucial to the success of your next project, so make sure you get it right. Expedition Co. can guide you with the best strategies and tools to bring your vision to life, including the best database architecture to use. To learn more about our web development services, contact us today and let’s start a conversation!