Patent ID: 7953761

Claim:
A structured-document retrieving system comprising: a plurality of document managing apparatuses that store a plurality of structured documents, which have layered logical structures, in a distributed manner; and a retrieving apparatus that is connected to the document managing apparatuses via a network and retrieves the structured documents from the document managing apparatuses, wherein the retrieving apparatus includes: a structure-information storing unit that stores, for each of the logical structures, statistical information of a structural element and a value in the structured documents corresponding to the logical structures; a rule storing unit that stores a rule in which a condition of the statistical information and an expression format are associated with each other, the expression format being a format for representing a character string that includes a structural element and a value; a plan generating unit that generates, based on a retrieval request for the structured document from a client terminal connected to the network, an execution plan of retrieval processing for the structured document; an acquiring unit that acquires, from the structure-information storing unit, the statistical information corresponding to the logical structure to be retrieved of the execution plan generated; an associating unit that acquires, from the rule storing unit, the expression format corresponding to the condition satisfied by the statistical information acquired and associates the expression format with the execution plan; a plan transmitting unit that transmits the execution plan associated with the expression format to the document managing apparatuses; a result receiving unit that receives a retrieval result, which is an execution result of the execution plan, from the document managing apparatuses; and a first result transmitting unit that transmits the retrieval result to the client terminal, and each of the document managing apparatuses includes: a plan receiving unit that receives the execution plan associated with the expression format from the retrieving apparatus; a plan executing unit that executes the execution plan received and outputs a retrieval result obtained by executing the execution plan in the expression format associated with the execution plan; and a second result transmitting unit that transmits the retrieval result represented in the expression format to the retrieving apparatus.