Storage Engine (using a store type) -> Data Store (ordered by data model) -> Database (providing semantics & management) k->v is a data store (using disk|inmem

Storage Engine (using a store type) -> Data Store (ordered by data model) -> Database (providing semantics & management) k->v is a data store (using disk|inmem|networked storage engines). A database is a complete system for management of data. They come (or used to come) in various data model flavors: hierarchical, graph, relational, etc.