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NoSQL vs SQL — What is your primary database?

· 6 min read
Deniz Colak

Databases are essential components of modern applications. They store and manage data, providing the backbone for the applications we use every day. There are two primary types of databases: SQL and NoSQL.

SQL, which stands for Structured Query Language, is the older and more established of the two. It has been the only selection for the users until 1998 and has since become the de facto standard for data management. SQL databases are relational, meaning that data is stored in tables with defined relationships between them.

NoSQL stands for not only SQL, is designed for unstructured or semi-structured data. It is a newer and more flexible approach to data management. Instead of using tables, NoSQL databases store data in a more flexible format, often as a document, graph, or key-value pair.

Which one is right for your needs? Let’s compare and contrast the two to help you make an informed decision.

At a glance

NoSQL databases are more flexible and easier to scale than SQL databases. However, SQL databases are better suited for applications that require complex queries, transactions, and consistency. If you're not sure which one is right for you, we recommend starting with a SQL database and moving to NoSQL if you need to scale.

Example SQL code to create a table
CREATE TABLE EMPLOYEE    employee_id INT NOT NULL,    first_name VARCHAR(20) NOT NULL,    last_name VARCHAR(25) NOT NULL,    DOB DATE NOT NULL,    SSN CHAR(11) NOT NULL,    salary DECIMAL(8,2) NOT NULL,);
Example NoSQL code to create a document
db.employee.insert({  employee_id: 1,  first_name: "John",  last_name: "Doe",  DOB: "1990-01-01",  SSN: "123-45-6789",  salary: 50000.0,});

What is SQL?

SQL databases store data in tables, with a specific structure defined by a schema. The schema defines the columns and the data types of each column and relations. This structure makes it easy to sort, and filter data. Some of the most popular SQL databases include MySQL, PostgreSQL, and Microsoft SQL Server.

2023 Top popular SQL databases
2023 Popular SQL databases - Source: db-engines.com

What is NoSQL?

Unlike SQL databases, they don't enforce a rigid structure on the data they store. This allows NoSQL database to scale horizontally and handle high volumes of traffic without slowing down. NoSQL databases can handle large amounts of unstructured or semi-structured data. Some popular NoSQL databases include MongoDB, Cassandra, and Couchbase.

2023 Top popular NoSQL databases
2023 Popular NoSQL databases - Source: db-engines.com

When to Use NoSQL?

NoSQL databases are best suited for applications that require high-speed writes and reads, and can handle unstructured or semi-structured data. They're also a good choice for web and mobile applications that experience rapid growth and unpredictable spikes in traffic.

NoSQL databases are a good choice when you need to store large amounts of unstructured or semi-structured data, such as images, videos, or log files. They're also good for real-time data, such as social media feeds or sensor data from IoT devices. If you have data that changes frequently, NoSQL is a good choice because it's easy to add or remove fields from documents.

When to Use SQL?

SQL databases are best suited for applications that require complex queries, transactions, and consistency, and can handle structured data. They're also a good choice for financial systems, enterprise resource planning (ERP) systems, and other applications that require consistent data and strict transactional consistency.

SQL databases are great for structured data that can be organized into tables. They're also good for data that requires transactions, like online shopping carts, bank transfers, and other types of data that need to be rolled back if something goes wrong. If you need to store data that has relationships between entities, such as a user and their orders, SQL is the way to go.

Key Differences Between NoSQL and SQL

Flexibility

NoSQL databases offer a high degree of flexibility, allowing developers to add and remove fields on the fly without having to make changes to the database schema. This makes it easy to accommodate changing business requirements and enables rapid development.

SQL databases, while less flexible, provide a well-defined schema that can be used to enforce data constraints and ensure data quality. This can be especially important for applications that require a high degree of data accuracy, such as financial systems and healthcare applications.

Performance

When it comes to performance, NoSQL databases have the edge over SQL databases in many cases. NoSQL databases are designed for high-speed writes and reads, making them a popular choice for applications that require real-time updates, such as online gaming, social media, and e-commerce.

On the other hand, SQL databases excel at complex queries and transactions, making them a good fit for financial applications, enterprise resource planning (ERP) systems, and other applications that require consistent data and strict transactional consistency.

Scalability

NoSQL databases are known for their ability to scale horizontally, adding more nodes to the database cluster as needed to handle increased traffic. This makes NoSQL databases a popular choice for web and mobile applications that experience rapid growth and unpredictable spikes in traffic.

SQL databases, on the other hand, are designed to scale vertically, meaning you add more resources such as memory and CPU to the database server to handle increased load. This can be more expensive than scaling horizontally and may result in a single point of failure if the database server fails.

The Bottom Line

In the end, the choice between NoSQL and SQL databases comes down to the specific needs of your application. If you need a database that can handle high-speed writes and reads, flexible data structures, and can scale easily to handle high volumes of traffic, then a NoSQL database may be the way to go. If, however, you need a database that can handle complex queries, enforce data constraints, and ensure consistent data, then a SQL database may be a better choice.

Here's a code snippet to illustrate the difference between the two:

Example SQL code to create a table
CREATE TABLE users (    id INT AUTO_INCREMENT PRIMARY KEY,    name VARCHAR(255),    email VARCHAR(255));INSERT INTO users (name, email)VALUES ('John Doe', '[email protected]');SELECT * FROM users WHERE name='John Doe';
Example NoSQL code to create a document
db.users.insert({  name: "John Doe",  email: "[email protected]",});db.users.find({ name: "John Doe" });

Whether you choose SQL or NoSQL, the important thing is to choose the right tool for the job. Both SQL and NoSQL have their strengths and weaknesses, and the best choice depends on your specific needs. If you need help making a decision, don't hesitate to reach out to us! We're here to help.