Описание тега key-value-store
Key/Value stores allow the application to store its data by composing `(key, value)` pairs.
Key/Value stores allow the application to store its data in a schema-less way.
The data can be stored in a datatype of a programming language or an object. Because of this, there is no need for a fixed data model.
The following types exist:
- Eventually consistent;
- Hierarchical;
- Cache in RAM;
- Solid state or rotating disk;
- Ordered.
Source: http://en.wikipedia.org/wiki/NoSQL#Key.E2.80.93value_stores