作为一种去中心化的分布式账本, 区块链被广泛应用于互不可信的多方之间共享数据. 相比于发展多年的传统数据库, 区块链存在无法支持丰富查询、对外提供查询接口单一和查询响应慢的问题. 简单的组织结构和离散的存储方式是限制交易数据表达的主要原因. 为了弥补现有区块链系统的不足, 构建抽象模型、封装易于使用的接口以及提升查询效率是实现基于区块链的高效应用开发的主要方式. 鉴于此, 提出一种面向区块链的通用数据管理中间件, 具有如下特征: ①支持自定义构建数据模型, 灵活地为交易数据抽象新模型; ②提供多种数据访问接口支持丰富查询并采用同步缓存机制等优化方式提升查询效率; ③设计提前哈希计算和异步批处理策略优化交易的延迟和吞吐. 提出的数据管理中间件已集成于开源区块链CITA中, 并通过实验验证其易用性与高效性.

As a decentralized distributed ledger, blockchain technology is widely used to share data between untrusted parties. Compared with traditional databases that have been refined over many years, blockchains cannot support rich queries, are limited to single query interfaces, and suffer from slow response. Simple organizational structures and discrete storage limits are the main barriers that limit the expression of transaction data. In order to make up for the shortcomings of existing blockchain technology and achieve efficient application development, users can build abstract models, encapsulate easy-to-use interfaces, and improve the efficiency of queries. We also propose a general data management middleware for blockchain, which has the following characteristics: ① Support for custom construction of data models and the flexibility to add new abstractions to transaction data; ② Provide multiple data access interfaces to support rich queries and use optimization methods such as synchronous caching mechanisms to improve query efficiency; ③ Design advance hash calculation and asynchronous batch processing strategies to optimize transaction latency and throughput. We integrated the proposed data management middleware with the open source blockchain CITA and verified its ease of use and efficiency through experiments.