The address linker of an LDAP client has a capability of requesting retrieval of data in local files or retrieval of data in files registered on an LDAP server. The address linker of the LDAP server serves to share personal data and has a capability of retrieving data in files on the server and a capability of responding to data retrieval and registration request from the LDAP client. The LDAP client or server outputs a list of retrieval results and highlights latest data according to the updating date and time determined when pieces of personal data of the same name are registered in a plurality of files. The LDAP client or server further select latest data, reconstruct the data into a single file having a tree data structure and saves the file.