Patent ID: 7937390
Filing Date: 2011-05-03
Classification: G06F

Abstract:
1. A method for controlling a relational database system, wherein a query statement to be processed consisting of keywords is first analyzed by applying a recursive transition network (RTN), and the keywords or group of keywords are allocated processing-relevant properties in the order given by the statement, whereafter it is converted into control commands and optionally optimized, characterized in that it contains the following steps: defining the RTN in a presetting step by forming independent RTN building blocks, wherein each RTN building block includes associated processing-relevant building block information and has an inner, directed decision graph which is defined independently from the inner, directed decision graphs of the other RTN building blocks and has at least one decision path, which includes at least one decision position, with at least one part of the RTN building blocks having a recursive RTN building block introduction position at at least one of the decision positions of their decision paths, which prescribes the introduction and running of one of the RTN building blocks from the total of RTN building blocks, wherein the introduced RTN building block again optionally includes the recursive RTN building block introduction position in its decision graph at least once so that any number of nesting levels of RTN building blocks can be introduced, forming a reference group, the elements of which refer to a residual decision graph with the first decision position removed, wherein for each RTN building block the following substeps are carried out independently from the other RTN building blocks: so that after carrying out all substeps for all RTN building blocks, the reference group contains the first decision positions of all RTN building blocks, and these first decision positions refer to their associated residual decision graphs, running of all keywords of the statement to be processed by carrying out a reference processing step for the keyword at the first position of the statement to be processed, wherein the element matching the keyword is searched in the reference group and, when the same is found, the residual decision graph allocated thereto by reference is followed in a way that the respective subsequent keywords of the statement to be processed are run and all possible decision paths of the allocated residual decision graph are followed until either no matches with the respectively chosen decision path are detected and the reference processing step in question is aborted or the respectively chosen decision path is run to the end, wherein at those decision positions of the allocated residual decision graph reached that have a recursive RTN building block introduction position, the reference processing step is effected recursively, and that an access plan for the relational database system is generated from the order of the processing-relevant building block information and its nesting as resulting after running of all keywords of the query statement.