Abstract: A designator designates whether to perform normalization for registration data or retrieval data that has been input, but does not perform the normalization. A data processor performs the normalization process in accordance with the designator's designation. A register registers the registration data into a data storage, registers the registration data into a drawer, and sets a pointer. A retriever employs the retrieval data to retrieve the pointer from the drawer, and acquires the data from the data storage. The data processor performs a first normalization process by converting a character sequence in the registration data or the retrieval data to a precomposed character, and a second normalization process by converting a compatibility character in the registration data or the retrieval data to a predetermined character. The second normalization process converts half-width characters into full-width characters. The first normalization process is performable after the second normalization process.

Abstract: A technology is provided of obtaining a retrieval result suited for a user' desire in a case of retrieving data expressed by the code system such as UNICODE in which techniques of expressing one character exist in plural. With registration data including a composing character or a compatibility character, a key item being included in the registration data, which should be made retrievable with a normalized retrieval key as well, is normalized, and is registered into a drawer, and the key item being included in the registration data, which should be made unretrievable, is registered into the drawer as it stands.