PURPOSE: To form easily the joining due to a request from a terminal, by providing a link representing the relation between files to each field of a data base including plural files of data comprising plural fields.

CONSTITUTION: Data are inputted from a terminal 5 and a data base retrieval processing is executed with a host 1 in the form of conversation. A command processing section 2 performs entire managing control such as communication with the terminal and command analysis. A data processing section 3 executes the data base retrieval processing such as joining based on a file 7 of a data base file 6 according to a set retrieval key. A relation control section 4 selects and displays 5 sequentially the file 7 of the data base file 6 according to a relation table 9. Thus, the forming of a table joining required data in a short time is formed easily even if professional knowledge is less.