Method and/or system for the execution of transformations of hierarchically structured data and relational data

The invention subject to this document describes methods for data transformations for hierarchical documents and relational databases. Data transformations ensure the interoperability between different organisations as well as different tools. The XQuery-standard is an example for a language that allows to create such transformations. The invention claimed is suited to interpret and execute XQuery-defined transformations. It comprises methods that can also be applied on other transformation languages. A procedure is described that includes the compilation of mappings into a set of interconnected operators exchanging data in form of tuple streams, including several optimizations to improve the performance of the basic procedure and reduce memory- as well as hard-disk consumption.