Blockchain doesn't have the client-server architecture that most centralized databases follow. In fact, being an implementation of the Distributed Ledger Technology, Blockchain has no centralized servers at all. All the nodes in the network communicate directly with each other in a peer-to-peer system. For a blockchain database, each node/participant maintains, calculates and updates new entries into the database. All nodes work together to ensure they are all coming to the same conclusions, providing in-built security for the network. Database are distributed across the participant nodes and transactions are immutable. It maintains different nodes through the use of a peer-to-peer network and a distributed timestamping server, a blockchain database is managed autonomously.