1. An information processor to analyze the right of access to a database having a data file in a form of a structured document, the information processor comprising: a query automaton generation unit for generating a query automaton from a path expression in which a retrieval condition for the database is described; an access control automaton generation unit for generating an access control automaton from an access control policy in which an access control rule is described; and a logic operation unit for deciding access rights in database retrieval using the path expression by performing logic operations related to the query automaton generated by the query automaton generation unit and the access control automaton generated by the access control automaton generation unit.