For a project, I'm using Hyperledger Composer Fabric to create a blockchain for an integrated healthcare system for integrity and fast access purposes. I don't want to store the actual healthcare records on the blockchain because they'll be large. Instead, I was thinking of storing a hash of the record on the blockchain and storing the records in a database. What kind of database would be best? I've used relational databases and SQL before only. Could this suit? I've seen some people say to store the location of the data on the blockchain too, how would you do this? This is only a small project, so I'm looking for simple solutions rather than some I see which are for real, enterprise systems.