Is it a correct approach to store needed Azure Storage Table relations in Azure SQL database? For example, I may have a system that keeps track of Users and Books that they own. I would keep Users entities and Books entities in Azure Storage Table and the relations (idUser, idBook) in supporting Azure SQL table.
Is it a good approach? What will be the drawbacks of this solution?
EDIT: The motivation to do it is simply to lower cost. I'll need to store a lot of data, so I plan to use Azure Storage Tables, becuase SQL database will be simply to expensive. But in some scenarios I'll need to store relations between objects.