level of abstraction which is not only ideally suited for processing data on secondary storage but which also readily absorbs important issues in computational parallelism and in distributing data over the Internet. I review the simple ideas needed to push the relational model to its inherent full capabilities, and show the syntactic adjustments needed to avoid the limitations of conventional and commercial implementations. The discussion is prefaced by some motivating examples, without full explanations, and terminated by a consideration of some special techniques for implementing the language constructs.
T. H. Merrett