System and method for computing rows since sequence function in a database system
US6289336A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 26, 1999 |
| Grant date | Sep 11, 2001 |
| Priority date | — |
| Expiry date | Mar 26, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99934
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A database query compiler and compilation method has special facilities for compiling a query that includes a Rows Since sequence function, Rows Since (search condition). A query normalizer includes a Rows Since function normalizer for normalizing the Rows Since sequence function. The Rows Since function normalizer parses the search condition of the Rows Since function to identify each reference to information from a previously access row and converts each such identified reference into an Offset sequence function, Offset(argument, index). The argument of the Offset sequence function is a specified function of the identified information from a previously accessed row of the table. The previously accessed row has a position that is index rows before the current row referenced by the cursor for the table. The query compiler places the resulting normalized search condition in a search loop that traverses successively earlier rows in the table until it finds a row that satisfies the search condition. An offset sequence function compiler, compiles each Offset sequence function, Offset(argument, index), in the normalized database query into a compiled set of instructions, including instr…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.