The file-assignment and query-processing problems in local multiaccess networks

In this paper the distribution-design and query-processing problems for distributed databases on local multiaccess computer networks are studied. The broadcast capability of these networks allows information to be distributed efficiently. In the distribution-design problem, the distribution of independent files are studied. With the broadcasts of updates, the distribution of multiple copies of a single file can be solved optimally in polynomial time. However, the general problem with storage-capacity constraints is still NP-hard, and an efficient branch-and-bound method is proposed. In the query-processing problem, the semi-join concept is adopted. The propagation of reduction on dependent attributes is studied. Although the problem is NP-hard, less data transmission is needed with the broadcast of information.