64,941 research outputs found
Towards Intelligent Databases
This article is a presentation of the objectives and techniques
of deductive databases. The deductive approach to databases aims at extending
with intensional definitions other database paradigms that describe
applications extensionaUy. We first show how constructive specifications can
be expressed with deduction rules, and how normative conditions can be defined
using integrity constraints. We outline the principles of bottom-up and
top-down query answering procedures and present the techniques used for
integrity checking. We then argue that it is often desirable to manage with
a database system not only database applications, but also specifications of
system components. We present such meta-level specifications and discuss
their advantages over conventional approaches
A Definitional approach to the combination of functional and relational programming
We show how the programming language GCLA can be used to
naturally express both relational and functional programs in an integrated
framework. We give a short introduction to GCLA, and to the theory of
partial inductive definitions on which GCLA is based. GCLA is best
regarded as a logic programming language, but instead of saying that the
query follows from the program in some a priori given logic, we say that
the program defines the logic in which the query is proved. We then
demonstrate how to implement both relational and functional programs as
well as a combination of them in GCLA
A Relational Derivation of a Functional Program
This article is an introduction to the use of relational calculi in deriving programs. Using the relational caluclus Ruby, we derive a functional program that adds one bit to a binary number to give a new binary number. The resulting program is unsurprising, being the standard quot;, but the derivation illustrates a number of points about working with relations rather than with functions
Parallel asynchronous computation of the values of an associative function
This paper shows an application of a formal approach to parallel program design. The basic model is related to temporal logics. We summarize the concepts of a relational model of parallelism in the introduction. The main part is devoted to the problem of synthesizing a solution for the problem of parallel asynchronous computation of the values of an associative function. The result is a programming theorem, which is wide applicable for different problems. The abstract program is easy to implement effectively on several architectures. The applicability of results is investigated for parallel architectures such as for hypercubes and transputer networks
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