公开(公告)号：US6128610A

公开(公告)日：2000-10-03

申请号：US139526

申请日：1998-08-25

申请人： Jagannathan Srinivasan ,  Samuel De Fazio ,  Anil Nori ,  Souripriya Das ,  Chuck Freiwald ,  Jayanta Banerjee

发明人： Jagannathan Srinivasan ,  Samuel De Fazio ,  Anil Nori ,  Souripriya Das ,  Chuck Freiwald ,  Jayanta Banerjee

IPC分类号： G06F17/30

CPC分类号： G06F17/30321 ,  Y10S707/99932 ,  Y10S707/99933 ,  Y10S707/99943

摘要： A method and apparatus for efficiently storing and retrieving data in a database using index-only tables is disclosed. Storing a row of data in a database using index-only tables involves storing in a leaf node an index entry that includes a key value along with all other values in the row of data. If the row of data exceeds a predetermined size, then a portion of the row of data is stored in a user specified overflow area. Retrieving a row of data from an index-only table for a user-supplied key involves identifying a leaf node for the key, and reading a row of data from the index entry and any remaining portion from the overflow area when the row exceeds the predetermined size.

摘要翻译： 公开了一种使用仅索引表在数据库中有效地存储和检索数据的方法和装置。 使用仅索引表存储数据库中的一行数据涉及在叶节点中存储包含键值的索引条目以及数据行中的所有其他值。 如果该数据行超过预定大小，则该行数据的一部分被存储在用户指定的溢出区域中。 从用户提供的密钥的仅索引表中检索一行数据涉及识别密钥的叶节点，并且当该行超过预定的值时从索引条目读取一行数据和来自溢出区域的剩余部分 尺寸。

公开(公告)号：US5852822A

公开(公告)日：1998-12-22

申请号：US764112

申请日：1996-12-09

申请人： Jagannathan Srinivasan ,  Samuel DeFazio ,  Jayanta Banerjee ,  Chuck Freiwald ,  Souripriya Das

发明人： Jagannathan Srinivasan ,  Samuel DeFazio ,  Jayanta Banerjee ,  Chuck Freiwald ,  Souripriya Das

IPC分类号： G06F17/30 ,  G06F17/00

CPC分类号： G06F17/30327 ,  Y10S707/99933 ,  Y10S707/99934 ,  Y10S707/99936 ,  Y10S707/99952

摘要： A method and apparatus for building, maintaining, and using a multi-level index is provided. The multi-level index is accessed using a key. The key is divided into multiple portions referred to as sub-keys. The first level of the multi-level index is built on a first-level sub-key. Each index entry at the first-level is for a particular first-level sub-key value, and either includes sub-entries associated with second-level sub-key values or a reference to a second-level data retrieval structure. All second-level data retrieval structures are built on the portion of the key that has been designated as the second-level sub-key. As the vocabulary of the first-level sub-key becomes exhausted, fewer maintenance operations will have to be performed to maintain the first-level data retrieval structure. This decreases the overhead and increases the concurrency in a database system that uses the multiple-level index. The multi-level index structure is especially suited for queries that retrieve all values for a given first-level sub-key. The structure also has reduced storage costs compared to a single-level index structure, since first-level sub-key values are stored only once for each nested group.

摘要翻译： 提供了一种用于构建，维护和使用多级索引的方法和装置。 使用密钥访问多级索引。 密钥分为多个部分，称为子密钥。 多级索引的第一级建立在一级子密钥上。 第一级的每个索引条目用于特定的一级子密钥值，并且包括与二级子密钥值相关联的子条目或对二级数据检索结构的引用。 所有二级数据检索结构都建立在已被指定为二级子密钥的密钥部分上。 由于第一级子密钥的词汇量已经耗尽，因此维护第一级数据检索结构将不得不执行较少的维护操作。 这降低了开销，并增加了使用多级索引的数据库系统中的并发性。 多级索引结构特别适用于检索给定一级子密钥的所有值的查询。 与单级索引结构相比，结构也降低了存储成本，因为对于每个嵌套组，一级子键值只存储一次。