Besides SQL databases, Azure has some Not Only SQL (NoSQL) options, with Cosmos DB being Microsoft's very own solution. Cosmos DB is only available in the cloud and no on-premises version currently exists. Like Azure SQL, Cosmos DB is a PaaS solution. The cool thing about Cosmos DB is that it has APIs for all the major NoSQL models out there: the key-value model, the document model, the graph model, and the wide column model.
The Cosmos DB document API matches the popular MongoDB database API and the wide column API matches the Apache Cassandra database API, meaning that you can easily move those databases to Cosmos DB and your software will continue to work. Additionally, Cosmos DB has a SQL API. This doesn't mean your data is stored in a relational model; it simply means that a SQL layer was added over a document database. While Cosmos...