A wide-column store (or extensible record store) is a column-oriented DBMS and therefore a special type of NoSQL database.[1] It uses tables, rows, and columns, but unlike a relational database, the names and format of the columns can vary from row to row in the same table. A wide-column store can be interpreted as a two-dimensional key–value store.[1] Google's Bigtable is one of the prototypical examples of a wide-column store.[2]