To have a virtualization feature, we will consider the inclusion of features to manage distributed databases of similar types, the distributed databases of different types, and provide location transparency for users, such that they notice no differences of database structure or location and become able to use databases of all kinds in a flexible fashion. Fig.1 portrays a comprehensive view of a database virtualization technique. For virtualization of ubiquitous databases in our study, we will describe the schema information of the real databases, of which more than one always happens to exist, by creating and using one common XML schema. We also provide functionality of data search and update with the XML-based common data manipulation API. In the following, we will begin discussion of virtualization of the same type of distributed database followed by virtualization of different types of distributed databases.