As technology advances, the difference between NoSQL vs SQL databases can do are blurring. Developers flood tech forums with clever workarounds that let them stick to their favorite database, even when it doesn’t exactly fit.
This is a source of confusion for the c-suite seeking guidance on the best database for a specific project. No matter how hard the internet crowd argues that an experienced programmer can make any database work, there are very real structural differences between SQL and NoSQL.
Workarounds that disguise these differences result in unnecessary complexity, decreased performance, and higher development costs.
So how should a responsible leadership team choose? Start by brushing up on the benefits of both formats.
SQL: Orderly and Secure
SQL refers to relational database management systems (RDBMS) written purely in SQL. Data fields are organized into structured tables, and creators must clearly define the schema before adding data.
The rigid structure of a SQL database has some major advantages.
Advantages of SQL
The format emphasizes data integrity by minimizing redundancy, normalizing data, maintaining referential integrity, and enforcing strict constraints on what data can be entered or altered.
Using a SQL database provides better control of transactions compared to NoSQL databases.
A hyper-organized SQL database is also easier to query.
Handling large amounts of structured data
It’s suitable for projects with a large amount of structured data that needs to be regularly referenced and analyzed by non-engineers.
Anyone who knows how to structure simple SQL queries can pull information from the database (within the permissions imposed upon them by the administrator).
SQL databases have been on the market for a long time.
There’s a large community of users, so support is easy to find.
With many skilled developers and database administrators available, upper management can afford to be choosy about who they contract with or hire to handle their SQL database.
Disadvantage of SQL
The biggest drawback to an SQL database is its price.
Hosting and licensing fees are generally higher than with NoSQL databases. Most companies offer bundle discounts, but costs rise when developers want to mix and match products to more precisely suit their needs.
The leading RDBMS, Oracle, changed its pricing structure in January so that hosting with Amazon Web Services or Azure is significantly more expensive.
However, open source options like PostgreSQL or MongoDB can keep the price within an acceptable range.
NoSQL: Fast and Flexible
The name “NoSQL” is a bit misleading. It means “not only SQL” rather than “no SQL”. In a NoSQL database, data is stored in documents that contain loosely related chunks of information.
Developers don’t need to create schema before adding information; data can be dumped into the database and organized once it’s there.
Advantages of NoSQL
A NoSQL database is useful when the data requirements of a project aren’t clear up front, especially if it’s difficult to estimate how much of the data will be structured versus unstructured.
Use of Unstructured Data
Document databases are perfect for large volumes of unstructured data.
Document databases are ideal for rapid development. Installation is quick and easy. Because there’s less setup involved before adding data, they allow for fast, iterative prototyping.
IDEs are Abundant
In their infancy there weren’t many NoSQL tools, but today developers have a wide choice of integrated development environments (IDEs) to examine their data and run queries.
NoSQL databases are compatible with most development frameworks and platforms which provides flexibility in building the stack.
Plus, hosting is cheap on the production environment. Although a third party service is recommended afterwards, there are plenty of cost-effective cloud services to choose from.
Scalability is a powerful benefit to NoSQL databases. They are designed to be distributed across servers, making them scalable on short notice with little impact on performance.
Data is accessible and very fast compared to most common RDBMS.
Disadvantages of NoSQL
Dip in Quality
Of course, flexibility and performance come with a reduction in accuracy.
Not ACID Compliant
The majority of NoSQL databases are not ACID compliant. Many rely instead on the principle of eventual consistency, trusting that although data may be altered on one server it will become consistent across servers during the next update.
Number of Experts
Finding NoSQL experts may be tricky. There is a growing community, but since it’s a newer concept than RDBMS there’s a smaller pool of trained developers and database administrators. Some supporters have argued that the point of NoSQL is to do away with the need for a DBA, though in practice that isn’t yet feasible.
Making the Choice
As a general guideline, NoSQL databases shine when dealing with real-time big data, content management, and IoT applications. SQL databases take the lead in situations where complex queries need to be done often, as in online transaction processing and banking.
That said, asking whether a RDBMS or a NoSQL database is better without considering the project is futile. It’s about as helpful as asking whether to use a fork or a spoon before the meal has been ordered. Each project has unique needs. While SQL databases tend to be the default choice for developers, there’s no objectively “better” overall database philosophy.
To make the final decision, assess the scope of the project at hand.
Are the data requirements clear up front?
Developers can’t create schemas without direction. When there isn’t enough certainty about what type or how much data will be incoming, a NoSQL database may be the better option.
How much JSON data will you be handling as a percentage of the total?
Few projects will have entirely one type of data. If unstructured data is a relatively small portion of the whole and other considerations make an SQL database attractive, the SQL database will be able to handle it.
What’s more important, data integrity or performance?
When data integrity is the overriding priority, use SQL. If not, NoSQL generally has a noticeable edge in performance.
Will you need to cache and share data often?
This is a particular strength of NoSQL databases.
Is this a global or a local app? How fast will you need to scale?
Scaling a NoSQL database is as easy as adding more servers. An RDBMS scales up, not out, making for a slower process.
Are there relevant legal or trade restrictions?
Projects that handle a lot of protected data, such as HIPAA information, need to prioritize security and data integrity.
Once all the information has been gathered, one database style should stand out as the better option. If that doesn’t seem to be the case, take the problem to the developer. There’s a variety of both SQL and NoSQL databases; one may have a set of traits that solves the apparent dilemma. For instance, if a NoSQL database seems like a good fit but consistency is fairly important, the developer may recommend a database such as MongoDB which is strongly consistent (though not ACID compliant beyond the document level).