Apache Cassandra Explained in 5 Minutes or Less

Apache Cassandra is an open-source, NoSQL distributed database.

What Is Apache Cassandra?

Before being made open source, Apache Cassandra was designed initially at Facebook (now Meta) to combine features of Amazon’s DynamoDB and Google’s Bigtable.

It is widely used by companies such as Netflix, Uber, and Facebook because of its high availability and scalability.

This article will go through how Apache Cassandra is structured, how it works, and the different features and benefits of using it as part of your tech stack.

What Is NoSQL?

Apache Cassandra falls under the group of databases known as NoSQL databases. Unlike relational or SQL databases, NoSQL databases do not use SQL or relations in the way SQL databases do.

This creates advantages in ease of use and flexibility while sacrificing the ability to make more advanced queries. However, both NoSQL and SQL databases have their places where each one shines.

How Does Apache Cassandra Work?

Cassandras runs using the Cassandra Query Language (CQL), which is syntactically very similar to Structured Query Language (SQL) used by relational databases.

However, it does not support certain features, such as joins, that most relational databases have. This is because Cassandra is a query-first database. That means the database is designed based on the queries that will be made.

Tables are then created to provide enough data for each query without needing to join multiple tables. This makes it fast. It can be installed on all major operating systems.

Architecture of Cassandra

At the most basic level, Cassandra is made up of nodes. Data is stored in nodes, and all records with the same key are stored in the same node. This makes performing queries faster than in SQL databases, where multiple tables may be running on multiple machines.

Data is replicated across nodes for high availability by a replication factor specified by the database creator. A group of nodes storing the entire data in a database is called a data centre.

A group of data centres forms a cluster. Having multiple data centres means data is always available even when one data centre unexpectedly goes offline.

Features of Apache Cassandra

Among the most important and differentiating factors of Apache Cassandra and other options on the market are that it is:

#1. Open-Source

Apache Cassandra is free and open-source. This means the source code is available online, which makes it less likely that it has bugs and vulnerabilities that have not been discovered and fixed already.

This is important because user and business data are important assets that should be safeguarded.

#2. Uses Wide-Column Architecture

Unlike most databases that store data in files depending on which table the data is in, Apache Cassandra stores by column.

This makes searching for a value in a column faster because it does not have to look up the entire row. As a result, Cassandra’s data lookups are as fast as using indexes in other databases.

#3. Distributed

Apache Cassandra is distributed, meaning it does not run on a single machine. This helps ensure high data availability because it is replicated across different nodes and data centres. It also makes data access faster when data centres are geographically closer to the user.

#4. Query-First Design

In traditional database design, tables are modeled around entities. Through normalization, relationships between these entities are then established and created in the databases.

Often when querying, relationships span multiple tables. When these tables are stored on different machines, data access can be slow.

However, with Cassandra, you build tables based on the queries you intend to make. All the data needed to satisfy that query is then stored in one table.

Benefits of Apache Cassandra

• It is free: The database management system itself is free and can be downloaded from the official website of Apache Cassandra. However, the server infrastructure that the database runs on is not.
• Highly available: Apache Cassandra is designed with resilience in mind. It is designed with enough redundancy to remain functional when portions of the database go offline.
• It is scalable: Additional nodes can be added to the database, and storage capacity can be expanded with little to no downtime. This is ideal for building high-volume applications.
• It is faster: Because of the wide column architecture and query-first design., Apache Cassandra can perform faster compared to other database management systems.

Now, we will explore some of the best learning resources to understand Apache Cassandra.

Learning Resources

#1. Apache Cassandra: Everything You Need To Know

This Udemy course on Apache Cassandra will take you from beginner to pro lessons covering topics from the theoretical overview of Cassandra to the Cassandra Query Language.

The only requirement for this course is that you should be familiar with databases in general and Linux systems.

#2. Become a Certified Cassandra Developer: Practice Exams

This certificate course comprises two exams that will help you prepare and practice for the Datastax Academy’s Apache Cassandra Developer Certification exam.

Each exam is ninety minutes and covers topics from Architecture, Modelling, and Cassandra Query Langauge. The ideal audience for this course is developers who already know Cassandra but are looking to gain professional certifications.

#3. Apache Cassandra Essentials

This book for developers teaches you how to get started with Apache Cassandra. It teaches readers to install Cassandra and set up a database cluster. Next, you will learn the Cassandra Query Language to interact with your database.

You will also learn about tools you can use to monitor your cluster and debug queries. It is ideal for someone who has never worked with Cassandra before and is looking to get started.

#4. Mastering Apache Cassandra

Written for people with some prior knowledge of Cassandra, this book teaches readers to write more efficient Cassandra programs and configure Cassandra to be more performant.

Furthermore, it teaches how to integrate Apache Cassandra with Apache Spark to build data analytics systems.

Final Words

Apache Cassandra is a powerful choice for a database in large-scale, distributed systems. Its reliability, scalability, and speed make it a favored option among tech giants.

Learning and mastering this database will equip you with skills to build software systems that serve millions of users reliably.

Next, you can check out Apache Cassandra monitoring tools to keep an eye on database performance.