A computer-implemented method comprising: determining (S101), by a storage device, a data storage instruction, wherein the data storage instruction carries an identifier and data to be stored; determining (S102), by the storage device and based on the identifier, a blockchain that corresponds to the identifier and a key pair that corresponds to the identifier; storing (S103), by the storage device, the data to be stored in the blockchain based on the key pair; and accessing, by a query device, data that corresponds to the identifier by accessing the blockchain that corresponds to the identifier, wherein determining (S102) a blockchain that corresponds to the identifier and a key pair that corresponds to the identifier comprises: determining whether a blockchain that corresponds to the identifier exists in a blockchain network storage node based on a pre-stored mapping relationship between the identifier and each of the key pair and the blockchain; in response to determining that the blockchain that corresponds to the identifier exists in the blockchain network storage node, determining a blockchain that corresponds to the identifier and a key pair that corresponds to the identifier in the blockchain network storage node; and in response to determining that the blockchain that corresponds to the identifier does not exist in the blockchain network storage node, generating a blockchain that corresponds to the identifier and a key pair that corresponds to the identifier. determining (S101), by a storage device, a data storage instruction, wherein the data storage instruction carries an identifier and data to be stored; determining (S102), by the storage device and based on the identifier, a blockchain that corresponds to the identifier and a key pair that corresponds to the identifier; storing (S103), by the storage device, the data to be stored in the blockchain based on the key pair; and accessing, by a query device, data that corresponds to the identifier by accessing the blockchain that corresponds to the identifier, wherein determining (S102) a blockchain that corresponds to the identifier and a key pair that corresponds to the identifier comprises: determining whether a blockchain that corresponds to the identifier exists in a blockchain network storage node based on a pre-stored mapping relationship between the identifier and each of the key pair and the blockchain; in response to determining that the blockchain that corresponds to the identifier exists in the blockchain network storage node, determining a blockchain that corresponds to the identifier and a key pair that corresponds to the identifier in the blockchain network storage node; and in response to determining that the blockchain that corresponds to the identifier does not exist in the blockchain network storage node, generating a blockchain that corresponds to the identifier and a key pair that corresponds to the identifier. determining whether a blockchain that corresponds to the identifier exists in a blockchain network storage node based on a pre-stored mapping relationship between the identifier and each of the key pair and the blockchain; in response to determining that the blockchain that corresponds to the identifier exists in the blockchain network storage node, determining a blockchain that corresponds to the identifier and a key pair that corresponds to the identifier in the blockchain network storage node; and in response to determining that the blockchain that corresponds to the identifier does not exist in the blockchain network storage node, generating a blockchain that corresponds to the identifier and a key pair that corresponds to the identifier. <EOS>