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Supporting ancillary values from user defined functions in Oracle

机译：支持Oracle中用户定义函数的辅助值

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Most commercial SQL database systems support user-defined functions that can be used in WHERE clause filters, SELECT list items, or in sorting/grouping clauses. Often, user-defined functions are used as inexact search filters and then the filtered rows are sorted by a relevance measure. This is commonplace in Web search engines, multimedia, and personalization applications. We refer to the values, such as relevance measure, associated with the filtered rows as ancillary values, and address the problem of efficiently and expressively supporting queries involving them in Oracle. In our approach, the filtering operator is designated as the primary operator, and the associated ancillary values are modeled by additional operators that are declared to be ancillary to the primary operator. An ancillary operator can represent any auxiliary value for the filtered rows, including relevance values (e.g. a score which describes how well a document matches the text search query) and additional properties (e.g. the nature of spatial relationship for objects that overlap a given region). The query execution is optimized by allowing the primary and ancillary operator invocations to share computations via a shared context. Also, queries involving ancillary values can exploit user defined indexes and their capability to return results in the order of ancillary values. We present the key concepts, describes our implementation scheme and optimization techniques, and discusses alternative approaches for supporting ancillary values. Finally, we provide an experimental study that illustrates the scalability and effectiveness of our approach.
机译：大多数商业SQL数据库系统支持用户定义的函数，这些函数可以在WHERE子句过滤器，SELECT列表项或排序/分组子句中使用。通常，将用户定义的函数用作不精确的搜索过滤器，然后通过相关性度量对过滤后的行进行排序。这在Web搜索引擎，多媒体和个性化应用程序中很常见。我们将与过滤后的行相关联的值（例如相关性度量）称为辅助值，并解决了在Oracle中有效且富有表现力地支持涉及它们的查询的问题。在我们的方法中，将过滤运算符指定为主要运算符，并通过声明为主要运算符辅助的其他运算符对关联的辅助值进行建模。辅助运算符可以表示过滤后的行的任何辅助值，包括相关性值（例如，描述文档与文本搜索查询匹配程度的得分）和其他属性（例如，与给定区域重叠的对象的空间关系的性质） 。通过允许主操作员和辅助操作员调用通过共享上下文共享计算来优化查询执行。同样，涉及辅助值的查询可以利用用户定义的索引及其以辅助值顺序返回结果的能力。我们介绍了关键概念，描述了我们的实现方案和优化技术，并讨论了支持辅助价值的替代方法。最后，我们提供了一项实验研究，阐明了我们方法的可扩展性和有效性。

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