The rapid growth in the number users of global networks such as the Internet, the number of systems used by those users, the amount of the available information, and the growth in the bandwidth has made new demands towards finding new techniques for interoperating between the enormous information pools that already exist. Many people from companies, government, schools and individuals will have access to an increasing amount of data. Indeed, users have already started to access huge amounts of information from disparate sites. Thus, the problem typically associated with the (I) dispersal nature and size of the available data, (2) the heterogeneous nature of the data resources. The first problem, which is the dispersal nature and available size of information sources, is caused by many factors. The main one is the rapid connectivity of the local area networks, which forms the global backbone of the public Internet. Additionally, the success of linking the three-tier architecture (mainframe, mini, and Local Area Networks) has enlarged the size of the problem. Instead this has increased the number of databases becoming available over the Internet. Also, the advances in linking heterogeneous communication protocols maximize the size of the available information source. The second problem, which is the heterogeneous nature of the information sources, is mainly caused by the ongoing demand in the field of information presentation. The new powerful platforms that have emerged with the new data models such as the object-orientation which supports voice and video has changed the view of the new information requirements. The situation ends lip with new powerful information platforms coexisting with old legacy systems using hierarchical, network, and relational data repositories that cannot be discarded for many reasons. Most of which relate to the huge amount of information stored on them and the cost of translating and moving the information to new, platforms. Sometime, even if the data could be migrated to new platforms, the rewriting of the code may become almost an impossible process, which could be too costly. Furthermore, the information representation may differ in the similar function systems, which may be due to the differences in thinking between human beings. Sometimes, the representation of the information is derived by many factors such as the data owners' business requirements and other issues related to the data owner integration process of the new systems with the existing old systems. Metadata, of course, is the data about data. In software design, the metadata are the schema of a database such as the tables, relationships between tables, the types and characteristics of the data the tables contain including the different constraints govern the data. In object orientation this is equal to the class diagram of an object-oriented system such as classes, relationships, inheritance, attributes and methods. In political design, the metadata are the Constitution tinder which the system operates, any amendments to it, any laws clarifying or implementing the system, judicial decisions explaining it, and (least important of all in a government 'of laws, not of men') policy statements and orders of the executive. The current Internet web browsers are not designed to browse and support the interoperation of the heterogeneous schemas metadata information willing to interoperate. The cooperation means the heterogeneous information sources accessible to all the information consumers give the maximum freedom to them as if they are accessing information source of the type they ar-e familiarize with. By such capability, information consumers can expand their own information sources by adding to them records from other distributed information sources having similar information, which will expand their information domain and will give better answers especially in the statistical health related information. interoperate. information In this paper I anl presenting a technical perspective on the system architecture requirements for the heterogeneous databases interoperability in the light of the current Internet advances. I am negotiating the different issues related to the metadata hosting that forms the bases for integrating and aggregating the distributed heterogeneous information sources. In a further stage I am also negotiating the linkage between the information sources and the permitted user groups. The major contribution of the work in this ar-ea is to create a unified methodology to advertise about any schema type that is accessible as an information space using the web browser as our communicator between the global information producers and consumers. The proposed solution will require a specialized proxy server responsible to communicate the cooperating information producers and also a specialized sear ch engine responsible to keep the different information consumers informed about the available information space.
