论文标题
查询结果是随着时间的流逝（扩展版本）而在正在进行的数据库中保持有效的数据库
Query Results over Ongoing Databases that Remain Valid as Time Passes By (Extended Version)
论文作者
论文摘要
现在使用的时间点用于声明元组从开始点开始有效。对于数据库系统，正在进行的时间点具有深远的影响，因为它们随着时间的流逝而不断变化。最先进的方法通过将其实例化到参考时间来处理持续的时间点。实例化产生的查询结果仅在选定的时间有效，并且随着时间的流逝而无效。我们提出了一个解决方案，该解决方案在查询处理过程中将持续的时间点保持不变。我们通过在所有可能的参考时间上评估谓词和功能来做到这一点。这使查询结果独立于特定的参考时间，并产生随着时间流逝而保持有效的结果。作为查询结果，我们提出了包括参考时间属性的持续关系。参考时间属性的值受到谓词和函数的限制。我们描述并评估了PostgreSQL中正在进行的数据类型和操作的有效实施。
Ongoing time point now is used to state that a tuple is valid from the start point onward. For database systems ongoing time points have far-reaching implications since they change continuously as time passes by. State-of-the-art approaches deal with ongoing time points by instantiating them to the reference time. The instantiation yields query results that are only valid at the chosen time and get invalidated as time passes by. We propose a solution that keeps ongoing time points uninstantiated during query processing. We do so by evaluating predicates and functions at all possible reference times. This renders query results independent of a specific reference time and yields results that remain valid as time passes by. As query results, we propose ongoing relations that include a reference time attribute. The value of the reference time attribute is restricted by predicates and functions on ongoing attributes. We describe and evaluate an efficient implementation of ongoing data types and operations in PostgreSQL.
