Database system having logical row identifiers
    5.
    发明授权
    Database system having logical row identifiers 有权
    具有逻辑行标识符的数据库系统

    公开(公告)号:US06546394B1

    公开(公告)日:2003-04-08

    申请号:US09473073

    申请日:1999-12-28

    IPC分类号: G06F1730

    CPC分类号: G06F17/30339 G06F17/30321

    摘要: A database system having logical row identifiers (rowids) includes a secondary index which is traversed to locate a secondary index entry that includes a target secondary key value. Each secondary index entry also includes a logical rowid element. Each logical rowid element has both a primary key value element, and a datablock address element identifying a leaf block in an index-organized table that likely includes a row corresponding to the primary key value element. The leaf block is scanned to locate the row in the index-organized table that includes the target secondary key value and corresponds with the located, secondary index entry. A primary key scan is performed on the index-organized table if the row in the index-organized table is not located in the identified datablock.

    摘要翻译: 具有逻辑行标识符(rowid)的数据库系统包括遍历的次索引以定位包括目标辅助键值的辅索引条目。 每个辅助索引条目还包括逻辑rowid元素。 每个逻辑rowid元素都具有主键值元素和标识索引组织表中可能包括与主键值元素相对应的行的叶块的数据块地址元素。 扫描叶块以在索引组织表中找到包含目标辅助键值的行,并对应于定位的辅助索引条目。 如果索引组织表中的行不位于标识的数据块中,则在索引组织表上执行主键扫描。