Method of optimizing SQL queries where a predicate matches nullable operands
    11.
    发明授权
    Method of optimizing SQL queries where a predicate matches nullable operands 有权
    优化SQL查询的方法,其中谓词与可空操作数匹配

    公开(公告)号:US06996557B1

    公开(公告)日:2006-02-07

    申请号:US09504086

    申请日:2000-02-15

    IPC分类号: G06F7/00

    摘要: An optimization technique for SQL queries, a program storage device storing the optimization program, and an apparatus for optimizing a query is provided. A query is analyzed to determine whether it includes a predicate for matching nullable operands and, if so, it is transformed to return TRUE when all operands are NULLs. If the DBMS supports this new function, the predicate is marked. If not, the predicate is re-written into a CASE expression having two SELECT clauses. The query is then executed in the computer to efficiently retrieve data from the relational database.

    摘要翻译: 提供了一种用于SQL查询的优化技术,存储优化程序的程序存储设备以及用于优化查询的设备。 分析查询以确定它是否包含用于匹配可空操作数的谓词,如果是,则在所有操作数都为空时将其转换为TRUE。 如果DBMS支持这个新功能,则会标记谓词。 如果没有,则将谓词重新写入具有两个SELECT子句的CASE表达式。 然后在计算机中执行查询以有效地从关系数据库检索数据。

    Apparatus and method for skipping XML index scans with common ancestors of a previously failed predicate
    13.
    发明授权
    Apparatus and method for skipping XML index scans with common ancestors of a previously failed predicate 有权
    用以前故障谓词的共同祖先跳过XML索引扫描的设备和方法

    公开(公告)号:US07552119B2

    公开(公告)日:2009-06-23

    申请号:US11613757

    申请日:2006-12-20

    IPC分类号: G06F17/30

    摘要: An apparatus and method are disclosed for skipping XML index scans with common ancestors of a previously failed predicate. An XML index is scanned by an XML index scan to filter entries of the index matching at least one search value (predicate) of an XML query. When the XML index scan finds a matching entry, the entry is passed to an XPath evaluation component. The XPath evaluation component evaluates the entry against remaining predicates of the XML query for further qualification. When the XPath evaluation component disqualifies an entry, the XPath evaluation component provides feedback to the XML index scan to skip remaining entries comprising a common ancestor of the disqualified entry's path. The XML index scan can then efficiently skip index entries that will not qualify against the XML query.

    摘要翻译: 公开了一种用于跳过具有先前故障谓词的共同祖先的XML索引扫描的装置和方法。 通过XML索引扫描扫描XML索引,以过滤与XML查询的至少一个搜索值(谓词)匹配的索引的条目。 当XML索引扫描找到匹配的条目时,该条目将传递给XPath评估组件。 XPath评估组件根据XML查询的剩余谓词评估条目以进一步验证。 当XPath评估组件取消条目资格时,XPath评估组件向XML索引扫描提供反馈,以跳过包含不合格条目路径的共同祖先的剩余条目。 然后,XML索引扫描可以有效地跳过不符合XML查询条件的索引条目。

    APPARATUS AND METHOD FOR SKIPPING XML INDEX SCANS WITH COMMON ANCESTORS OF A PREVIOUSLY FAILED PREDICATE
    14.
    发明申请
    APPARATUS AND METHOD FOR SKIPPING XML INDEX SCANS WITH COMMON ANCESTORS OF A PREVIOUSLY FAILED PREDICATE 有权
    用于将先前失败的预测的常规防御者拖放XML索引扫描的装置和方法

    公开(公告)号:US20080154893A1

    公开(公告)日:2008-06-26

    申请号:US11613757

    申请日:2006-12-20

    IPC分类号: G06F17/30

    摘要: An apparatus and method are disclosed for skipping XML index scans with common ancestors of a previously failed predicate. An XML index is scanned by an XML index scan to filter entries of the index matching at least one search value (predicate) of an XML query. When the XML index scan finds a matching entry, the entry is passed to an XPath evaluation component. The XPath evaluation component evaluates the entry against remaining predicates of the XML query for further qualification. When the XPath evaluation component disqualifies an entry, the XPath evaluation component provides feedback to the XML index scan to skip remaining entries comprising a common ancestor of the disqualified entry's path. The XML index scan can then efficiently skip index entries that will not qualify against the XML query.

    摘要翻译: 公开了一种用于跳过具有先前故障谓词的共同祖先的XML索引扫描的装置和方法。 通过XML索引扫描扫描XML索引,以过滤与XML查询的至少一个搜索值(谓词)匹配的索引的条目。 当XML索引扫描找到匹配的条目时,该条目将传递给XPath评估组件。 XPath评估组件根据XML查询的剩余谓词评估条目以进一步验证。 当XPath评估组件取消条目资格时,XPath评估组件向XML索引扫描提供反馈,以跳过包含不合格条目路径的共同祖先的剩余条目。 然后,XML索引扫描可以有效地跳过不符合XML查询条件的索引条目。