A distributed database is a collection of multiple, logically interrelated databases distributed over a computer network. A Distributed Database Management System (DDBMS) is a software system that permits the management of distributed data making the distribution transparent to the user. This report reviews the issues that arise with such systems, surveys current commercially available DDBMSes, and summarizes the state of the art. Although no standards yet exist within this new technology, some guidelines have been provided by C. J. Date and E. F. Codd. True implementations of general purpose DDBMSes are only now beginning to emerge in the marketplace. Their implementations with respect to issues of distributed database technology differ markedly.