NewBatch returns a batch.

NewCachedBatch returns a new cached batch buffer.

NewKVCache returns a KVCache.

NewWriteInfo creates a new write info.

Delete indicate the type of write operation to be Delete.

Put indicate the type of write operation to be Put.

ErrAlreadyDeleted indicates the key has been deleted.

ErrAlreadyExist indicates certain item already exists in Blockchain database.

ErrNotExist indicates certain item does not exist in Blockchain database.

ErrOutOfBound indicates an out of bound error.

ErrUnexpectedType indicates an invalid casting.