摘要 |
A query in which a sibling relationship among document parts, which are elements of a structured document, can be designated as a search condition is input, and a query tree which represents the query in a tree structure is created. A query converting unit refers to a hierarchical index in which a hierarchical relationship among document parts of each structured document to be searched is expressed in a tree structure, and converts the query tree to a Boolean expression. A text-index referring unit refers to a text index in which is registered information representing a relationship between each set including a character string in text data and a part-ID of a meta part and a document-ID of a document, thereby searching a document corresponding to the Boolean expression converted from the query tree.
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