论文标题
查询在没有完整性约束的路径视图上重写
Query Rewriting On Path Views Without Integrity Constraints
论文作者
论文摘要
具有绑定模式的视图是数据库上的参数化查询。使用此类视图，例如为Web服务建模。要回答有关此类观点的查询，必须在执行计划中共同协调观点。目的通常是找到等效的重写，该重写与所有数据库中的查询完全相同。但是，这种重写通常只有在存在完整性约束的情况下才能 - 并且并非所有数据库都有这样的约束。在本文中，我们描述了一类计划，即使没有完整性限制，也可以实践保证其结果。我们提供了此类计划的特征和完整而正确的算法以列举它们。最后，我们证明我们的方法可以找到现实世界Web服务的计划。
A view with a binding pattern is a parameterised query on a database. Such views are used, e.g., to model Web services. To answer a query on such views, one has to orchestrate the views together in execution plans. The goal is usually to find equivalent rewritings, which deliver precisely the same results as the query on all databases. However, such rewritings are usually possible only in the presence of integrity constraints - and not all databases have such constraints. In this paper, we describe a class of plans that give practical guarantees about their result even if there are no integrity constraints. We provide a characterisation of such plans and a complete and correct algorithm to enumerate them. Finally, we show that our method can find plans on real-world Web Services.
