Some earlier reports in [1], [2] have described the study of database virtualization technology. One report [1] proposed development of a system to pass information actively to all users in a mobile computing environment without fail, as sourced from various types of database groups connected by a wide-area network. By image-copying of the data of the local database group to a meta-database through the basic search and build operations, for example, it is intended to combine data and include different types of the local database group.