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

An index generation method includes: executing an extraction process that includes extracting a plurality of morphemes from document information; and executing 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'.