Patent ID: 7246107

Claim:
A processor-implemented database search system, comprising: a database for storing a document file; a database control unit for controlling a transfer of a document file to and from said database; a search engine for searching said database on the basis of a keyword comprised of a character string, and for returning a search result to said database control unit; an index file for use in a search process by means of said search engine, for retaining information indicating a correspondence of said keyword to positional information of the keyword, based on a field in the document file that includes said keyword; wherein the index file comprises a key file that includes a list of pointers to character strings and positional information; wherein the character strings are included in the document file and are stored in the database by document area where a character string in the document file appears and by a positional information file; wherein the positional information file includes a list of positional information containing information that specifies the document file where a character string exists and information that specifies a position of the character string in the document file regarding the character string in the key file; and wherein for a variable-length chain included in the index file, a relational file is created by dividing each word in the variable-length chain into a plurality of fixed-length keywords.