Graph databases represent a significant growth area. Indeed, research suggests that it is the fastest growing segment of the database market. There are arguably three reasons for this growing interest and each pertains to a particular sub-sector of the graph market. The first is that graph databases are designed to handle many-to-many relationships, which relational databases are not, so graph products have particular advantages in operational and transactional environments where this is the case. The second is with respect to semantics, which is of growing importance in its own right, and which graphs handle with ease. The third is that many graph analytic algorithms require a significant degree of iteration, which is not available with MapReduce and, where many-to-many relationships are involved, are not easily parallelised in conventional warehousing environments.