The relational data model has become the most important model for database systems. The primary virtues of the model are its rigorous mathematical foundations and the correspondence of a relation with the notion of a ...
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The relational data model has become the most important model for database systems. The primary virtues of the model are its rigorous mathematical foundations and the correspondence of a relation with the notion of a table. The success of the relational paradigm for traditional database applications (i. e. , data processing) has led researchers to consider its use in other applications such as computer-aided design (CAD) databases, knowledge bases and user-interface modeling. These non-traditional applications of the relational model have drawn attention to several weaknesses in the model. A promising approach to dealing with these weaknesses is the incorporation of alternative language paradigms into relational languages. We survey extensions to relational languages and propose directions for further extension of the model. These extensions include nested relations and aspects of object-oriented and functional programming.
Early generic concepts in programminglanguages were mixed-type arithmetic (e.g., “+” used with any combination of fixed-and floating-point numbers) and “print” functions which could be applied to any of a languag...
ISBN:
(纸本)9781450374408
Early generic concepts in programminglanguages were mixed-type arithmetic (e.g., “+” used with any combination of fixed-and floating-point numbers) and “print” functions which could be applied to any of a language's objects. Generic concepts reduce the number of terms which must be remembered and permit considerable condensation of language design. Three different paths in the development of generic-concept languages have been followed by APL, Algol 68, and object-orientedlanguages such as SIMULA 67 and Smalltalk. APL was the earliest and one of the most interesting applications of generic-concept methods, but now makes the weakest use of these *** talk will use slides and movies to show how the message-objectprogramming system Smalltalk makes use of generic concepts embedded in class descriptions to give rise to a wide variety of simply programmed dynamic simulations including graphic animation, music synthesis, document layout and retrieval, and APL-like calculation features. Many of these systems have been brought to life by child and adult novice programmers.A short list of references is given for those wishing more introductory information about Smalltalk.
The SPECL programming system is an attempt to combine the characteristics of an implementation language with those desirable for verifiability (human and mechanical) and transportability. The former requires efficient...
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GLOSS is a machine and language for modeling the semantics of programminglanguages. GLOSS is not intended to be a tool for mathematical proofs. Instead it is intended to provide an easily read graphical notation in w...
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