Database query set-up tool and method for setting up a query

摘要

A database query set-up unit comprising a contribution stack and means for deriving a current information state from said contribution stack is described. Any search criteria provided by any user or by the system itself is pushed onto said contribution stack in the order of occurrence. The current information state, which is used for actually accessing the database, is formed from a subset of the set of search criteria contained in said contribution stack. In order to relax the search constraints, it is possible to suppress one or more of the search criteria contained in said contribution stack when forming the current information state. By implementing a contribution stack, it is possible to keep track of the order of occurrence of the various user inputs and system contributions, and to use this information for relaxing the search constraints. <IMAGE>