1. A system for querying hierarchical data, the system comprising: a query component for receiving a query of a database query language comprising query input relevant to the hierarchical data, the query input expressly including rowset structure information; and a hierarchical data processor for receiving the hierarchical data and for receiving the generated query from the query provider, and for processing the received query to extract the rowset structure information relevant to the hierarchical data, and for generating rowset data corresponding to the hierarchical data based on said rowset structure information.