The switch from relational hadn’t been too hard because Riak is a key-value store, which made modeling relatively easy. Key value-stores are relatively simple database management systems that store just pairs of keys and values.

McCaul reckoned, too, migration of data had been made possible because the structure of patient records lent themselves to Riak’s key-value mode

via NHS grows a NoSQL backbone and rips out its Oracle Spine • The Register.