NoSQL is a catch-all term to describe various types of databases that use non-relational models. Some database paradigms grouped under the 'NoSQL' label include:
- Key-Value pair and distributed key value store databases that store and retrieve a record based on a main or supplementary key.
- Document databases that store a structured document based on a key, possibly with supplementary indexes.
- Graph and object databases.
Commonly cited strengths of NoSQL systems include easy scale-out capabilities, flexibility with schema structure and making trade-offs against ACID properties (for example 'eventual consistency' semantics) for performance.
May also sometimes be referred to as Not Only SQL