确定访问的相关性（扩展版）
Determining Relevance of Accesses at Runtime (Extended Version)
摘要：
考虑这样一种情况：使用Web源来回答查询，这些Web源通过要求将某些属性作为服务的输入来限制对后端关系数据的访问。这些访问提供对匹配绑定的属性值集合的查找。它们的不同之处在于是否需要从先前的访问生成参数。先前的工作集中在是否可以使用一组数据源来回答查询的问题上，并且集中在开发静态访问计划（例如，实现查询应答的数据库程序）。我们感兴趣的是动态方面的查询回答问题：给定的部分信息的数据，访问可以提供相关的数据回答一个给定的查询？我们认为即时和长期的概念“相关访问”，并确定查询相关性的复杂性，合取查询和任意的积极查询。在这个过程中，我们涉及到访问限制下的查询包容的动态相关性，并描述了这个问题的复杂性，我们产生了几个复杂的结果，由自己感兴趣的包容。
英文摘要：
Consider the situation where a query is to be answered using Web sources that restrict the accesses that can be made on backend relational data by requiring some attributes to be given as input of the service. The accesses provide lookups on the collection of attributes values that match the binding. They can differ in whether or not they require arguments to be generated from prior accesses. Prior work has focused on the question of whether a query can be answered using a set of data sources, and in developing static access plans (e.g., Datalog programs) that implement query answering. We are interested in dynamic aspects of the query answering problem: given partial information about the data, which accesses could provide relevant data for answering a given query? We consider immediate and long-term notions of "relevant accesses", and ascertain the complexity of query relevance, for both conjunctive queries and arbitrary positive queries. In the process, we relate dynamic relevance of an access to query containment under access limitations and characterize the complexity of this problem; we produce several complexity results about containment that are of interest by themselves.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
