Data management method, device and system and storage medium

The invention provides a data management method, device and system and a storage medium, relates to the technical field of block chains, and is used for solving the problem that the overall performance of the block chain is influenced by using MPT to store account data and contract data. The scheme comprises the steps of creating a target transaction; if the target transaction comprises a storage instruction for the account data, storing the account data to a data node of a single Merkel B + tree; if the target transaction comprises a storage instruction for contract data of one contract account, the contract data is stored to a data node of a Merkel B + tree corresponding to one contract account, and different contract accounts correspond to different Merkel B + trees; the last layer of the Merkel B + tree is data nodes, and other layers of the Merkel B + tree are index nodes; the root of the Merkel B + tree corresponding to one contract account is stored in the root field of the account data of one contract