Stores data as columns which consists of a name/value pair. Columns can be grouped into column families in a nested fashion. You are able to access any given column given a row key as well as all columns that share a row key. Values are timestamped which is used to handle conflict resolution. Additionally, most store row keys in lexicographic order; allowing for efficient look ups of row keys and their columns.
These are often used for large volume datasets and offer high availability and scalability. Some examples include:
- Google Bigtable
- Cassandra