Patent ID: 8117187
Filing Date: 2012-02-14
Classification: G06F

Abstract:
1. A method for controlling a relational database system, the method comprising the steps of: executing a database query in a relational database which contains, as an associated data structure, a plurality of data tables interconnected through relations, by using a database language, and with a table of the relations being provided; creating a database statement, which does not contain any relation-related operations; determining an access path, which concretely states an order of access to the relational database, wherein the database statement created contains only processing functions, data tables and columns of the data tables to which the processing functions are to be applied as well as order and levels of hierarchy of the data tables according to which processing the query is to take place, wherein the order and levels of hierarchy of the data tables used are represented in form of an ordered tree, and root of the ordered tree contains all names of the data tables of the database query only, and subordinate sub-queries are subordinate to the root and listed in the tree-structure as nodes, which contain names of the data tables associated with the sub-queries, wherein in the table of relations, the relations are indicated as links between two data tables each via at least one key field, wherein the access path is determined by first computing a partial access path, via the table of relations, between each two subsequent, selected data tables on the basis of the relations which exist between each two subsequent, selected data tables, and then assembling the access path from all computed partial access paths; and producing a SQL statement which can be processed by any database system supporting the SQL standard by introducing into the database statement relation-oriented operations by means of the access path, which has been determined using the table of relations.