Index generation method, data retrieval method, apparatus of index generation

A data retrieval method comprising:

• accepting a search string with respect to document information;
• referring to index information including a first logical value indicating existence of a morpheme which is associated with morpheme information indicating the morpheme and position information indicating a position of the morpheme in the document information and a second logical value indicating existence of the morpheme which is associated with attribute information indicating a semantic attribute of the morpheme and the position information indicating the position of the morpheme with respect to each of a plurality of morphemes included in the document information;
• performing a logical operation by using a third logical value associated with a retrieval morpheme included in the search string and a fourth logical value associated with a semantic attribute of the retrieval morpheme in the index information;
• and
• outputting a retrieval result of the search string based on a result of the logical operation.

An apparatus of index generation, the apparatus comprising:

• a memory;
• and
• a processor coupled to the memory, the processor being configured to
• execute an extraction process that includes extracting a plurality of morphemes from document information;
• and
• execute a generation process that includes generating index information with respect to each of the plurality of morphemes,
• wherein the index information includes a first logical value and a second logical value,
• wherein the first logical value indicates existence of a first morpheme associated with ‘morpheme information indicating the first morpheme’ and ‘position information indicating a position of the first morpheme in the document information’, and
• wherein the second logical value indicates existence of the first morpheme associated with ‘attribute information indicating a semantic attribute of the first morpheme’ and ‘position information indicating the position of the first morpheme’.