Abstract: A method for controlling a relational database system by 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, with a table of the relations being provided. A processable database statement without relation-related operations is created by indicating the data tables to which the processing functions are to be applied and by indicating the order of the selected data tables according to which the processing is to be carried out, and an access path, which concretely states the order of access to the database, 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 the subsequent data tables, and then assembling the access path from all computed partial access paths.

Abstract: A method for controlling a relational database system, with a query statement comprised of keywords being analyzed, with the RTN being formed of independent RTN building blocks. Each RTN building block has an inner, directed decision graph which is defined independently from the inner, directed decision graphs of the other RTN building blocks with at least one decision position along at least one decision path. The inner decision graphs of all RTN building blocks are run by means of the keywords in a selection step and all possible paths of this decision graph are followed until either no match with the respectively selected path is determined by the decision graph and the process is interrupted, or the respectively chosen path is run until the end.

Abstract: A method for controlling a relational database system by 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, with a table of the relations being provided. A processable database statement without relation-related operations is created by indicating the data tables to which the processing functions are to be applied and by indicating the order of the selected data tables according to which the processing is to be carried out, and an access path, which concretely states the order of access to the database, 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 the subsequent data tables, and then assembling the access path from all computed partial access paths.