9. A database processing device processing a database modeled as an edge-labeled tree, comprising: a memory; a controller coupled to the memory, the controller identifying at least one path of the edged-labeled tree that does not contain desired information and processing the database with a composite automation which includes a schema having known structure and unknown structure, to retrieve the desired information without processing the identified path of the edge-labeled tree.
9. A database processing device processing a database modeled as an edge-labeled tree, comprising: a memory; a controller coupled to the memory, the controller identifying at least one path of the edged-labeled tree that does not contain desired information and processing the database with a composite automation which includes a schema having known structure and unknown structure, to retrieve the desired information without processing the identified path of the edge-labeled tree. 10. The device of claim 9, wherein the controller generates an automaton based on the desired information, generates the composite automaton by combining a schema of the database with the automaton, and analyzes the composite automaton to identify broken paths.