A Graph Query Processor for Queries of Class CRPQagg

在这个项目中，我们将通过设计和开发一个用于图形数据库的通用查询处理器来解决传统数据库研究中的这些需求。在这个项目中进行的研究将分为两个工作流程。第一个工作流将从属于定义良好的查询语言类的具体图形查询语言开始，从“自上而下”的问题入手。为了正式定义通用的图形数据模型和统一的运算符代数，将分析该类中流行的查询语言的功能。第二项工作将从图形操作和索引结构的现有算法开始，“自下而上”地解决这个问题。系统地研究图的特征和完成某一处理任务的可能算法之间的依赖关系。基于这项经验研究，将得出一个分析成本模型，该模型将两个工作流的结果联系在一起，以便建立一个查询处理器，该查询处理器将逻辑图形处理任务转换为优化的物理执行计划。

In this project, we will address these requirements in the tradition of database research by designing and developing a general query processor for graph databases. The research conducted in this project will be structured into two streams of work. The first stream of work will approach the problem "top-down" by starting from concrete graph query languages that belong to a well-defined class of query languages. The functionality of popular query languages in this class will be analyzed in order to formally define a common graph data model and a unified algebra of operators. The second stream of work will address the problem "bottom-up" by starting from existing algorithms for graph operations and index structures. The dependencies between the characteristics of a graph and the possible algorithms to accomplish a certain processing task will be studied systematically. Based on this empirical study, an analytical cost model will be derived that will tie the results of both streams of work together in order to build a query processor that translates logical graph processing tasks into optimized physical execution plans.