If you want to use Hyperledger Fabric effectively, you have to understand its key concepts. This includes ledger, chaincode, and channel.
The ledger is the sequenced, immutable, entire historical record of all state transactions. All the transactions that are performed will be added to the ledger. We can find the entire transaction history for each channel. A fabric blockchain ledger has two types of data—a world state and a blockchain transaction ledger. The world state, which is stored stored in a database, LevelDB, is the default database. The state data is mutable. It has a version number that keeps incrementally updated when the state changes. On the other hand, the ledger data is immutable, and is stored as a file. It records transaction data block information, which contains a sequence of transactions. Each block's header includes a hash of the block's transactions, as shown in the following diagram:
