Glossary · Database

NoSQL

A category of databases that store data in non-tabular formats such as documents, key-value pairs, graphs, or wide columns.

NoSQL (Not Only SQL) databases provide alternatives to the traditional relational model. They fall into several categories: document stores (MongoDB, CouchDB) that store JSON-like documents; key-value stores (Redis, DynamoDB) optimized for simple lookups; column-family stores (Cassandra, HBase) designed for wide, sparse datasets; and graph databases (Neo4j, Amazon Neptune) for highly connected data. NoSQL databases typically sacrifice some relational guarantees (like strict ACID compliance) in favor of horizontal scalability, flexible schemas, and high performance for specific access patterns. They are commonly used for real-time applications, content management, IoT data, and scenarios where the data model evolves frequently.

Fig — every answer ships with the tables, rows and SQL behind it.