Document databases focus on storage and access optimization for documents as opposed to rows or records. The document database entities are just records with multiple fields. All of the current document databases support documents in JSON (JavaScript Object Notation) format. Some document databases are BigTable databases, others provide MapReduce processing, while some of them are columnar databases. The inference is that the storage and access implementation is independent of the database’s orientation towards document-oriented databases. Some document databases provide added capabilities such as SQL or SQL-like query processing capabilities. For instance, Terrastore document store provides advanced
scalability and elasticity features without sacrificing Consistency.