SQL (Structured Query Language) databases:
Pros:
- SQL databases are typically better for complex queries because of their adherence to ACID (Atomicity, Consistency, Isolation, Durability) properties.
- They use a structured query language and therefore are extremely versatile in querying data.
- SQL databases are usually table-based, which makes them a good fit for applications that require multi-row transactions such as financial applications.
Cons:
- They tend not to scale horizontally very well (i.e., across multiple servers), and adding capacity can be time-consuming and expensive.
- A high level of skill is required to manage and maintain the databases.
- They are not a good fit for hierarchical data storage.
NoSQL databases:
Pros:
- NoSQL databases are usually designed to scale horizontally, and they can handle large amounts of data and traffic.
- They can store different types of data models: key-value, wide column, graph, or document-based. This makes them highly flexible.
- NoSQL databases can be easier to set up and manage, and they can often handle unstructured and semi-structured data.
Cons:
- NoSQL databases do not have a standard interface like SQL, which means that different types of NoSQL databases can be radically different from each other.
- They usually don’t support ACID properties, making them less reliable in terms of data consistency in some scenarios.
- While they’re designed to scale, they can have trouble with complex transactions and queries.