ABSTRACT

Figure A-5 model, for data management systems.26 This framework consists of three layers. One can think of the component technologies, which we will also refer to as components, belonging to a particular layer to be more or less built upon the technologies provided by the lower layer. Layer I is the Database Technology and Distribution Layer. This layer consists of database systems and distributed database systems technologies. Layer Π is the Interoperability and Migration Layer. This layer consists of technologies such as heterogeneous database integration, client-server databases, multimedia database systems to handle heterogeneous data types, and migrating legacy databases.27 Layer ΙΠ is the Information Extraction and Sharing Layer. This layer essentially consists of technologies for some of the newer services supported by data management systems. These include data warehousing, data mining, Internet databases, and database support for collaborative applications.28·29 Data management systems may utilize lower level technologies such as networking, distributed processing, and mass storage. We have grouped these technologies into a layer called the

Supporting Technologies Layer. This supporting layer does not belong to the data management systems framework. This supporting layer also consists of some higher-level technologies such as distributed object management and agents.30 Also, shown in Figure A-5 is the Application Technologies Layer. Systems such as collaborative computing systems and knowledge-based systems which belong to the Application Technologies Layer may utilize data management systems. Note that the Application Technologies Layer is also outside of the data management systems framework.