Whether you are developing an application for internal use or you are a SaaS company and want to sell a platform to make millions, there are many decisions you must make to ensure you get it right.

Some of the most vital decisions you make will centre around how you will structure your databases. While you have many options, Structured Query Language (SQL) remains a popular choice and is a familiar language for many developers. At the same time, NoSQL databases are also growing in popularity.

What are the differences, and how can you choose the right option for you if your choice boils down to these?

Here is all you need to know about SQL and NoSQL to help you understand how to make the right choice for your business.

Why is SQL still important?

Large companies typically use SQL to help them manage their databases, but that does not mean it is not suitable for your startup! If your business works with big data in a structured manner, SQL can help you gather, manage, compare, and change data from multiple sources at the click of a button.

Depending on your business, SQL can therefore help drive automation in both a back and front-end context. This means your business processes become more efficient, both internally and for your customers. A better customer experience means your business grows, which means you are winning.

Yet, SQL might not always be the best option to meet your needs.

What are the differences between SQL and NoSQL databases?

Tech experts and developers spent many years debating what NoSQL means. Some still are! The best way to frame this is to look singularly at SQL and NoSQL.

What is an SQL database?

SQL databases support the SQL language. SQL databases are known as "relational databases," which rely on tightly structured data and fixed schemas. SQL databases are "vertically scalable," meaning you can improve your database's performance by adding processing power and memory to your systems.

Due to the structured nature of SQL databases, they are often best used in a transactional context, and as such the following types of business may benefit from using SQL:

• eCommerce platforms
• Customer relationship management SaaS platforms
• Accounting software

What is a NoSQL database?

What does “NoSQL" mean to you? Many people interpret this as indicating a database does not use SQL. However, today it is accepted as referring to a database that does not use "only SQL." In simple terms, it is a database that might use SQL, but that uses other languages, too.

NoSQL started to come to the fore around 15 years ago, primarily in reaction to the drawbacks widely associated with SQL databases, namely:

• The lack of ability to scale horizontally – by adding more servers.
• The constraints the rigidity of the structured data in SQL brought to developers.

While you might be reading this and think the benefits and added possibilities of NoSQL sound fantastic, it is vital to appreciate you might not need them! If SQL does the job you need it to, choosing NoSQL could be adding complexity to your data management unnecessarily.

NoSQL can, however, allow you to work more dynamically with data, and is useful if:

• You need to create and store documents with undefined and unique structures.
• You want to add fields to databases and documents without changing existing fields and rules.
• You would benefit from using multiple databases with unique structures.

Pros and cons of SQL and NoSQL: How do they compare?

To add further context to the differences between SQL and NoSQL, we have summarised the pros and cons below.

SQL databases

Pros of SQL databases

• SQL databases reduce your data storage footprint, delivering more efficient performance.
• Robust data integrity due to the structure and schemas used.
• Flexible query support; your SQL engine will optimise queries and find the correct or most relevant answer within your structured data in the absence of an exact match.

Cons of SQL databases

• Use of rigid data models means careful design is needed to ensure adequate performance.
• Changing schemas and structures typically means database downtime.
• Scaling horizontally – adding more servers – is challenging, albeit not impossible.
• You need to ensure you use replication or failover techniques to mitigate the risk of database failure.

NoSQL databases

Highlighting the pros and cons of NoSQL databases is challenging because the pros and cons are unique to each use case depending on what languages you use alongside SQL. However, we summarise some of the potential benefits and disadvantages below.

Pros of NoSQL databases

• Scalable and eliminate single points of failure, so might be more reliable than SQL databases.
• Allow you to use flexible data models and update schemas as you go depending on your needs and feedback.
• High performance achievable by limiting the range of database capability.
• Ability to work with abstract data in various ways, including the creation of APIs for internal or customer use.

Cons of NoSQL databases

• As a distributed system, NoSQL databases can lead to specific outages, albeit without a single point of failure. However, you will still need to manage bugs that occur within particular areas of your process.
• Potential lack of flexibility in access patterns.
• As data is unstructured, or not as structured, query engines may struggle to provide best-case outcomes.

When to use SQL vs NoSQL databases: What is right for 2021?

It depends on the needs of your business and what you are looking to achieve.

As well as thinking about the specific recommended uses outlined earlier, consider the pros and cons of each, which are effectively trade-offs depending on your choice. In reality, if you need to work with NoSQL as a matter of necessity, you do not really have a choice, as SQL simply will not cut it. The primary considerations here are for those who would typically use SQL, and whether you need or would benefit from using NoSQL databases instead.

Choose the solution that is going to work best for you and your customers!