The database management system design largely depends on database architecture. There are various architectural types as centralized, decentralized, hierarchical, etc. There are also single, two-tier, three-tier, and multi-tier architectures in place. For example, an n-tier architecture may divide the entire database system into independent but related ‘n’ modules, each of which can be modified, changed, altered, managed, and replaced independently.
In single-tier architecture, the database management system is the only entity where the users locate on the DBMS and explore it. Any changes done by the authorized users will directly reflect on the same DBMS itself. Such an architecture may not offer any handy add-on tools to the end-users. The database designers or programmers, most of the time, prefer to use the one-tier architecture model.
In DBMS 2-tier architecture, it may be having an application layer through which the end-users can access the database. Programmers may use the 2-tier architecture in which they access the DBMS through an application. Here the second tier of application stands fully independent of the DB in terms of its programming, design, and operations. Here in this article, we will discuss the next architecture model more deeply, which is widely used, the 3-tier architecture.
Three-Tier architecture
3-tier architecture is a custom model of software architecture comprising three distinct layers of logical and standalone computing. This model is used frequently in applications that feature client-server systems. Typical 3-tier architecture provides many advantages in developing and producing environments by modularizing the three layers as user interface, underlying business logic, and data storage.
This modular approach will offer greater flexibility to the enterprise development teams and update specific parts of the application independent of the other parts. This add-on flexibility will help improve the speed of development and also reduce the time-to-market significantly. The development teams can easily upgrade or replace the independent tiers without tampering the other parts.
For example, the user interface of the given web application can be revamped without touching the underlying business logic and data access. Such an architectural database model is ideal for integrating and embedding any third-party applications into the existing system. This flexibility for integration also makes it appropriate for integrating any analytics software into the pre-existing apps and is mostly used by the embedded analytics application vendors. Most of the 3-tier architectures are used in both on-premise and cloud applications and virtually on the SaaS (software-as-a-service) applications.
The 3-layer model
As we have seen above, 3-tier architecture functions on three distinct layers. Let us further review how RemoteDBA.comexplores each of these layers in more detail.
- Tier 1: Presentation layer
The presentation tier can be considered the front end of the 3-tier systems, consisting of a standard user interface. This UI is often a graphical interface that can be accessed through a web browser or web application. It displays the content and info, which is useful to end-users. This primary tier is usually built using web development and technologies like HTML, CSS, JavaScript, or other front-end web development languages. This layer usually communicates with the different two layers through API calls.
- Tier 2: Application layer
The application tier will consist of the business logic, which decides the functional aspect of the system. This layer helps to derive the core competencies of the database application. This 3-tier architecture layer is coded using the functional programming language like .NET, Java, Python, C#, C++, etc.
- Tier 3: Data layer
The data-tier in the 3-tier system consists of the actual database, which functions as the storage and access layers. Examples of data layer systems are the standard relational and non-relation databases like MySQL, PostgreSQL, Oracle, MS SQL Server, Cassandra, MongoDB, Maria DB, etc. Data from this layer is accessed using API calls by the application layers.
Structure of 3-tier architecture
In a typical 3-tier architecture, the structure of deployment may be as below.
- The presentation layer (tier one) is deployed on the user machine as a desktop, laptop, tablet, smartphone, etc. This is usually operated through a web browser or web application by using the webserver.
- The application layer, which underlies the presentation layer, is usually hosted on one or more application servers. Still, it can also be hosted on the cloud or dedicated workstation based on the processing power and complexity needed for the application.
- The third layer, i.e., the data layer, will comprise a single or multiple relational or non-relational databases, sources of big data, data lakes, or other types of database management systems hosted on the cloud on-premise.
Benefits of three-layer architecture
There are many benefits in using this model of database architecture, which include but are not limited to increased developmental speed, better performance, scalability, flexibility, and availability. Modularizing different layers of the application will give the development team many better opportunities to enhance the product by ensuring greater speed than relying on a single code base. This can also improve the efficiency of development by letting the teams focus more on their core competencies than being compromised with limited avenues.
Scalability is the most wonderful advantage of 3-tier architecture. Each of these layers can be upscaled independently based on the user’s need at any given point. Suppose you start to receive an increased number of web requests, but these do not usually affect the application layer. In that case, you can scale up the web servers without altering the application servers. Similarly, if you find there are a greater number of application requests only from a limited number of users, then you can work on scaling up the application layer and data layer by setting aside the web servers.
By having distinct standalone layers, 3-tier architecture will let you increase your database applications’ availability and reliability by hosting different layers on different servers and by leveraging cached results. With full-stack systems, you need to worry about a single server performance or the risk of it going down, but in a 3-layer model, decreasing dependencies by separating each part of the application will help eradicate the performance issues offer you better throughput.
