This article presents and discusses the computation and communication model used by R*, a prototype distributed database management system. An R* computation consists of a tree of processes connected by virtual circuit communication paths. The process management and communication protocols used by R* enable the system to provide reliable, distributed… (More)
System R supports a high-level relational user language called SQL which may be used by ad hoc users at terminals or as an embedded data sublanguage in PL/I or COBOL. Host-language programs with embedded SQL statements are processed by the System R precompiler which replaces the SQL statements by calls to a machine-language access module. The precompilation… (More)
A relational approach makes this experimental data base management system unusually easy to install and use. Some of the decisions made in System R design in order to enhance usability also offer major bonuses in other areas.
R* is an experimental prototype distributed database management system. The computation needed to perform a sequence of multisite user transactions in R* is structured as a <italic>tree</italic> of processes communicating over virtual circuit communication links. Distributed computation can be supported by providing a server process per site which performs… (More)