Meet BigchainDB. The blockchain database.
It has some database characteristics and some blockchain properties, including decentralization, immutability and native support for assets.
At a high level, one can communicate with a BigchainDB network (set of nodes) using the BigchainDB HTTP API, or a wrapper for that API, such as the BigchainDB Python Driver. Each BigchainDB node runs BigchainDB Server and various other software. The terminology page explains some of those terms in more detail.