Data service provides unified data model for cross-domain data integration, and generates data view through data services composition. A challenging problem is once a primitive data service is updated, how to propagate the update bottom-up to the top level via several intermediate composite data services, and to ensure the update efficiency of the data view. In this paper, the data operations and their properties are analyzed to facilitate transformation of composite data services, and generate some equivalent composite data services from a user defined composite data service. In addition, the time cost model for the incremental update of a composite data service is built. The model measures the time cost of updating a composite data service within a time unit in terms of the update frequency and data volume of the primitive data services. Based on the model. A data view update optimization algorithm is proposed to minimize the time cost. Experiments show that our approach can effectively improve the update efficiency of the data view.%数据服务为实现跨域数据集成提供了统一的数据模型,并且可通过组合的方式支持用户定义数据视图,当底层的数据服务发生数据更新时,数据更新需要自下而上经过多个中间复合数据服务传播到顶层的数据视图.一类挑战性问题是,如何在这个传播的过程中保障数据视图的更新效率.为此,文中规范化数据服务的操作及其性质,并且根据用户的组合结果,通过复合数据服务的等价变换,生成运行效果相同的多种数据服务组合方案.同时,建立复合数据服务的更新代价模型,该模型能够利用底层数据服务的更新频率和请求频率,衡量复合数据服务的更新代价.基于该模型,文中提出最小化更新代价的数据视图的更新优化算法,利用该算法可以为用户推荐优化的数据服务组合方案.实验表明,该方法能够提高数据视图的更新效率.
展开▼
