Patent ID: 6853992

Claim:
A structured-document search apparatus for searching structures and text data of structured documents, the apparatus comprising: first store means for storing a hierarchical index that represents a hierarchical relationship among document parts and is expressed in a tree structure in which each of a plurality of meta parts forms a single node, the document parts being elements of each of the structured documents, and the document parts that are common in structure among the structured documents being regarded as the meta parts; second store means for storing a text index in which information representing a relationship between a set and a document-ID is registered, the set having a character string in text data and a part-ID identifying a meta part, and the document-ID being an ID of a document in which the character string and the meta part appear; and search means for searching a structure from the hierarchical index on the basis of a query tree that represents a query in the tree structure, and for searching a document corresponding to the query tree by referring to the text index on the basis of a search result on the structure, the query designating search conditions that express relationships among the document parts, including a sibling relationship in the tree structure, the search means comprising first refer means for referring to the hierarchical index and for converting the query tree to a Boolean expression in which a set having a character string and a part-ID is used as a single search key, and second refer means for referring to the text index and for obtaining a document-ID of a document corresponding to the query tree by use of the Boolean expression, hierarchical index creating means for judging, for corresponding document parts of respective structured documents to be subjected to search, whether the document parts are meta parts that satisfy conditions in which each of the nodes shares a common upper meta part and has a same element name and a same offset in a row of sibling parts in the document, the hierarchical index creating means setting, for the node information regarding the offset in the row of sibling parts in the document, a link extending from a child node to a parent node, and a link extending to another node having the same element name by assigning a part-ID to the document parts and registering as a node of the hierarchical index, when the document parts are meta parts.