CHARACTER-STRING RETRIEVING SYSTEM

PURPOSE:To execute the retrieval processing at high speed by constituting the title system so that comparison processing of a character is not executed with respect to a part having no possibility that a retrieval character-string is contained. CONSTITUTION:A character-string forward retrieving means 9 executes a comparison processing with a retrieval character-string only with regard to a part in which an arranged state of a 1 byte system character group and a 2 byte system character group is the same as an arranged state of a 1 byte system character group and a 2 byte system character group in the retrieval character-string, and also, the length of each character group is longer than length of the corresponding character group in the retrieval character-string. Also, a character-string reverse retrieving means 10 executes the comparison processing with the retrieval character-string only with regard to a part in which an arranged state of a 1 byte system character group and a 2 byte system character group is the same as an arranged state of a 1 byte system character group and a 2 byte system character group in the retrieval character-string, and also, length of each character group is longer than length of the corresponding character group in the retrieval character-string. In such a way, the processing of a forward direction retrieval and a reverse direction retrieval is executed at a high speed.