Search method using an index file and an apparatus therefor

A search method, for using an index file consisting of a key file, which includes key character strings, and a position data file, having position data corresponding to the key character strings, said search method comprising the steps of:

• correlating a position data delete flag with a specific key character string;
• and
• deleting, from said position data file, position data that correspond to said specific key character string, wherein, when said position data delete flag corresponding to a specific key character string, is set, position data for said key character string is not added to said position data file for said index file;
• and wherein, when said position data delete flag, corresponding to a specific key character string, is not set, position data for said key character string is added to said position data file for said index file.

An apparatus comprising:

• a new difference index preparation unit for preparing a new difference index file using a newly registered document, said index file consisting of a key file, which includes key character strings, and a position data file, having position data corresponding to the key character strings;
• an index merge unit for merging a conventional index file with said new difference index file prepared by said new difference index preparation unit, for determining whether a position data file is to be deleted by the steps of correlating a position data delete flag with a specific key character string;
• and deleting, from said position data file, position data that correspond to said specific key character string, and wherein said position data are deleted when the size of the position data, corresponding to said specific key character string, reaches a specific ratio, and for preparing a new index file;
• and
• a search unit for beginning a search based on said new index file generated by said index merge unit.

A program storage device readable by machine, tangibly embodying a program of instructions executable by the machine to perform method steps for using an index file consisting of a key file, which includes key character strings, and a position data file, having position data corresponding to the key character strings, said search method comprising the steps of:

• correlating a position data delete flag with a specific key character string;
• and
• deleting, from said position data file, position data that correspond to said specific key character string, wherein, when said position data delete flag corresponding to a specific key character string, is set, position data for said key character string is not added to said position data file for said index file;
• and wherein, when said position data delete flag, corresponding to a specific key character string, is not set, position data for said key character string is added to said position data file for said index file.

An apparatus comprising:

• a new difference index preparation unit for preparing a new difference index file using a newly registered document, said index file consisting of a key file, which includes key character strings, and a position data file, having position data corresponding to the key character strings;
• an index merge unit for merging a conventional index file with said new difference index file prepared by said new difference index preparation unit, for determining whether a position data file is to be deleted by the steps of correlating a position data delete flag with a specific key character string;
• and deleting, from said position data file, position data that correspond to said specific key character string, and wherein said position data are deleted when the size of said position data reaches a specific value that corresponds to said specific key character string, and for preparing a new index file;
• and
• a search unit for beginning a search based on said new index file generated by said index merge unit.

An apparatus comprising:

• a new difference index preparation unit for preparing a new difference index file using a newly registered document, said index file consisting of a key file, which includes key character strings, and a position data file, having position data corresponding to the key character strings;
• an index merge unit for merging a conventional index file with said new difference index file prepared by said new difference index preparation unit, for determining whether a position data file is to be deleted by the steps of correlating a position data delete flag with a specific key character string;
• and deleting, from said position data file, position data that correspond to said specific key character string, and wherein, when said position data delete flag corresponding to a specific key character string, is set, position data for said key character string is not added to said position data file for said index file;
• and wherein, when said position data delete flag, corresponding to a specific key character string, is not set, position data for said key character string is added to said position data file for said index file, and for preparing a new index file;
• and
• a search unit for beginning a search based on said new index file generated by said index merge unit.