Method for controlling a relational database system

A method for controlling a relational database system, wherein a query statement consisting of keywords is first analyzed by applying a recursive transition network (RTN) and by allocating process-related properties to the keywords or group of keywords in the order given by the statement after which follows a conversion into control commands and optionally an optimization,

• characterized in that
• the RTN is formed of independent RTN building blocks, wherein 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,
• wherein the decision paths at least partly have a recursive call function on at least one of the decision positions through which one of the RTN building blocks is run as a result of applying the selection step to all of the RTN building blocks, so that any frequently recursively nested execution of the selection step starting from the at least one of the decision positions is made possible,
• and in that an access plan for the relational database system is generated from the order of the RTN building blocks and their nesting as a result of the application of the selection steps on all keywords.