| 摘要 |
PROBLEM TO BE SOLVED: To form a customer service system allowing all the information references concerning service using identifiers of customers for public utilities, by which customers can easily know, regardless of the move of the customers. SOLUTION: This customer service system is provided with a customer database file, and the file is stored with a first identifier and a second identifier attached to identify data concerning each customer. The first identifier is invariable with respect to each customer, and the second identifier is changeable one or more times. The first identifier is related to the second identifier which is the first on time series, and the second identifier is related to the second identifier in the following order on time series. Among these second identifiers, the second identifier which is the first on time series is provided with data indicating the first, and the second identifier which is the last on the time series is provided with data indicating the last. |
