Microsoft Azure platform is supporting Hadoop implementations, SQL Server interoperability drivers for Hadoop has also been announced, Microsoft Research is trying to develop project Dryad, which are all movement towards building capabilities to support unstructured data. Graph databases are one of the prominently used database types in the world of unstructured data. Many would argue why relational database cannot be used to achieve the same what graph databases are used for ? Here is one of the answers for the same. Graph databases apply graph theory and once you understand the same you would find the reason why RDBMS cannot cater what Graph Databases can. Neo4j is one of the leaders in this area. Industry leaders like Google also have their own implementation of graph database know as Pregel.
sones GraphDB is one of the graph databases of choice for Microsoft professionals, as it is developed using .NET and is easily supported on Azure platform. Huge volume of unstructured data needs flexible compute and storage platforms like Azure cloud platform, and as it is using .NET framework behind the scenes, it is ideal to be hosted on Azure platform. You can access the technical datasheet from here and below is the architecture diagram of the same. Interestingly this brings a new query language for DB professionals, GraphQL !!