What are the different types of databases?

Document Database

One of the most common non-relational databases. A document database controls a collection of named string fields and object data values in an entity known as a "document." Document databases offer a large deal of flexibility by not requiring that all documents maintain the same data structures. Documents are commonly saved as JSON files, which can be encoded using a number of different methods, including XML, YAML, JSON, BSON, or plain text.