A data transmission method includes the steps of generating a data characteristic table and a retrieval data table in a memory area on a server side (S102, S103); converting items of the tables into serial form and combining them to generate transmission data (S104); attaching control data corresponding to the characteristics of the transmission data (S108); transmitting the data to a client machine (S110); regenerating the data characteristic table and the retrieval data table in a memory area on the client side (S203); and reading predetermined data from the regenerated table (S204). This method increases the data transmission rate, decreases the response time, and increases the efficiency of use of the database.