... on these topics.Multidatabase systems are discussed in [7, 96 , 193 , 194 , 205, 412, 420, 451, 452, 522, 558, 672, 697 ]; see [95 , 421, 595 ] for surveys.Internet Databases 6 49 An example of a real ... these operations).Parallel and Distributed Databases 641performance database systems, parallelism will be the key. Scheduling in parallel database systems is discussed in [454]. [431] contains ... theInternet Databases 661Commercial database systems and XML: Many relational and object-relational database system vendors are currently looking into support for XML intheir database engines....