A rapid advancement in wireless communication technology has lead to extend the services of static database systems to mobile users. Mobile computing is characterized by some intrinsic constraints related with available connectivity, power and hardware resources. When Mobile-Unit requires access to enterprise data, it is not practical to rely on a constant wireless connection to a Server for this access, since radio devices drain batteries quickly, and wireless links are expensive in any-time or any-place, therefore, data that need to be manipulated should be replicated from the enterprise database Server to middleware device. Proxy server (Mobile Host) gives the application a desired level of flexibility to react changes happening in the environment. This work is designated to improve the ability of Mobile-Units to query the middleware devices database as web database after replicating the data needed by Mobile-Units from Server to middleware local storage. One of the benefits of web database responses is to get faster transfer times which leads to minimize the transfer costs, and decreases power and memory consumption of mobile devices. This system search for a database (requested from Mobile-Units) that may exist in different Servers through heterogonous network protocols; the designed system provides the ability to access heterogeneous databases management systems to query different portions of tables in the same database or other databases and replicate it in the new generated middleware database.