In a Cloud environment, companies often use different kind of data to store. There are data like email, images, video, pdf, graph etc. in a Cloud environment. To store this data often NoSQL databases are used.
A NoSQL database like MongoDB provides storage and retrieval of data that cannot be stored efficiently in a traditional RDBMS.
Database like Neo4J provides features to store graph data like Facebook, LinkedIn etc. in a cloud environment.
Hadoop like database help in storing Big Data based information. It can handle very large-scale information that is generated in a large-scale environment.