NoSQL has different database technologies that facilitate to build modern applications, especially in Agile Development. The benefit of NoSQL Databases over Relational Databases (RDB) are:
Relational databases require that schemas be defined before you can add data. For example, if you want to store data of a customer like name, age, phone number, RDB needs to know what to store (columns) in advance.
However, it does not work well in Agile Development, because each time you complete new features, the schemas are often changes. We hardly can predict what to implement or how the schemas look like before implementing. So, if you want to store the gender of customers, for example, you may need to modify the schema's property to add a new column, and then migrate the entire database. There is almost no way to effectively address data which is completely unstructured or unknown in advance when using RDB.
NoSQL DB allows inserting data without a predefined schema. It is easy to make significant changes without worrying about service interruptions.
If you just think about hard rules and validation when adding data into the schemas, NoSQL still allows you to make these rules as well.
In RDB, we need to specify the data type for each column in a schema. For example, integer, float, double, bigint, binary, etc.
Using NoSQL, developers no longer need to worry about these fixed data types. They can be structured, semi-structured, unstructured and polymorphic data.
Because RDB is structured, it usually scales vertically. When the application becomes larger hence more queries come to the database, you can only scale it up by adding more computing power and memory to a single database server. However, this method gets expensive quickly.
The solution to this problem is horizontal scaling (or 'Sharding') - adding more servers instead of focusing more capacity in a single server. Sharding can be implemented in RDB, but it needs complex configuration and coding because RDB does not offer this feature natively. Therefore, developers take on more work to implement it across many servers. For example, writing code to decide:
In contrast, NoSQL databases support auto-sharding. It means they can natively and automatically spread data across servers, without caring about these above concerns.
Some NoSQL databases also offer fully managed, integrated in-memory database management layer
NoSQL databases are fully self-healing, offering automated failover and recovery, as well as the ability to distribute the database across multiple geographic regions to withstand regional failures. Nonetheless, RDB requires to manual implementation to support this feature.
In RDB, to query a record, you need to learn SQL syntax such asa SELECT fields FROM table WHERE ...
In NoSQL, querying is done through OOP APIS.
RDB were not designed to cope with the scale and agility challenges that face modern applications using Agile Development. Furthermore, RDB were they built to take advantage of the commodity storage and processing power available today. In this article, I have presented six benefits of NoSQL over Relational Databases.