which physically integrates a number of databases by converting the data into a unified database schema, as in IGD.  The main advantage is local control of data, while the main drawback is the update problem associated with the multiple databases, especially with their continual format changes and growing complexity and volume.  The hypertext navigation, as in SRS, is a “loosely coupled’ approach that employs the browsing model wherein hypertext-linked Web pages are followed for more information and are always one mouse click away.  While it is powerful for direct interaction, users may need to switch to separate windows to see the concerted annotation or become lost in cyberspace. store a rich collection of links and their associated summary information.  The latter will alleviate potential problems associated with timely collection of information from distributed sources over the net.  The concept is similar to that of the Virgil database [Achard et al., 1998], which was developed to model the concept of rich links (the link itself and the related pieces of information) between database objects.