Key-Value (Key-Value) storage database Key to Value key-value pairs, usually with a hash table to achieve fast lookup data unstructured (usually only treated as a string or binary data) content caching, mainly used to deal with a large amount of data, high access load, but also used in some logging systems.

Column storage database, to the column cluster storage, will be the same column of data exists together to find fast, scalable, easier to carry out distributed expansion function is relatively limited to distributed file system.

Document-based database, Key-Value corresponds to the key-value pairs, Value for the structured data, data structure requirements are not strict, the table structure is variable (do not need to pre-define the table structure as relational database), query performance is not high, and the lack of a unified query syntax, Web applications.

Graph (Graph) database, graph structure, the use of graph structure related algorithms (such as shortest path addressing, N-degree relationship lookup, etc.), many times you need to do the calculation of the entire graph in order to derive the information needed, and this structure is not very good to do distributed cluster programs, social networks, recommender systems.