Marc Andries and Jan Paredaens. A language for generic graphtransformations. In G. Schmidt and R. Berghammer, editors, Graph-Theoretic Concepts in Computer Science: Proceedings of the 17th International Workshop, WG '91, number 570 in Lecture Notes in Computer Science, pages 63--74, Fischbachau, Germany, June 17--19 1991. Springer-Verlag.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....di# cult, and so they are unsuitable for our purposes. The intermediate language Lean by Barendregt et al. 6] is another generic graph grammar language, with a similar drawback. There have also been many papers on implementing database queries and transformations using graph grammars [2,3,40], but again these contain constructs which make partitioning di#cult. Specifically for parallel applications, Janssens and Rozenberg [56] give a theoretical result where they model the behaviour of an Actor grammar using graph transformations. Barthelmann and Schied also use graph grammars as the ....

Marc Andries and Jan Paredaens. A language for generic graphtransformations. In G. Schmidt and R. Berghammer, editors, Graph-Theoretic Concepts in Computer Science: Proceedings of the 17th International Workshop, WG '91, number 570 in Lecture Notes in Computer Science, pages 63--74, Fischbachau, Germany, June 17--19 1991. Springer-Verlag.

....to the languages TL [AV90] and DL [AV91a] which are known to express exactly all computable database transformations. So, NIQL is well understood, and also very powerful. 5 In [AK89] it was conjectured that that IQL is fully determinate complete, but this was later shown to be false [Abi90, AP92] It is interesting to consider restrictions on the unlimited non determinism that NIQL programs allow. For motivations we refer to [VdBVG92] To find sensible such restrictions, one can get inspiration from the definition of determinate transformation. That definition required that two ....

M. Andries and J. Paredaens. A language for generic graphtransformations. In Graph-Theoretic Concepts in Computer Science, volume 570 of Lecture Notes in Computer Science, pages 63--74. Springer-Verlag, 1992.

....in S in and resulting in relations over a superscheme of S out 5 can be interpreted as a determinate query from S in to S out . The language CQL, however, is not complete with respect to the determinate queries. This can already be seen at the level of individual input output pairs of instances [1, 5]. Let Q be a determinate query, and suppose Q(I ; J) The only 5 Relation names used only for intermediate computations may be ignored. correspondence between I and J that can be derived from Definition 1 is that each automorphism in Aut(I) can be extended to an automorphism in Aut(J) A ....

M. Andries and J. Paredaens. A language for generic graph-transformations. In Graph-Theoretic Concepts in Computer Science, Proc. Int. Workshop WG 91, LNCS 570, 63--74. Springer-Verlag, 1992.

.... s are new objects. This can be easy visualized using graphs: starting from a discrete graph containing two isolated A nodes a 1 ; a 2 , a C cycle of four new nodes b 1 ; b 4 is created such that two opposite b nodes are associated to a common a node through the B relation. It can be shown [2, 9, 27] that such a query Q is not expressible in RA new loop. The non completeness of RA new loop can be put in a more structured framework using the notion of instance with copies [4] Let S be a scheme, and let S 0 S. For each R 2 S Gamma S 0 , let CR be a relation name not in S for which ....

M. Andries and J. Paredaens. A language for generic graphtransformations. In Graph-Theoretic Concepts in Computer Science, volume 570 of Lecture Notes in Computer Science, pages 63--74. SpringerVerlag, 1992.

....and so they are unsuitable for our purposes. The intermediate language Lean by Barendregt et al. BvEG 87] is another generic graph grammar language, with a similar drawback. There have also been many papers on implementing database queries and transformations using graph grammars [AE93, AP91, FV82] but again these contain constructs which make partitioning difficult. Specifically for parallel applications, Janssens and Rozenberg [JR90] give a theoretical result where they model the behaviour of an Actor grammar using graph transformations. Barthelmann and Schied also use graph ....

Marc Andries and Jan Paredaens. A language for generic graphtransformations. In G. Schmidt and R. Berghammer, editors, GraphTheoretic Concepts in Computer Science: Proceedings of the 17th International Workshop, WG '91, number 570 in Lecture Notes in Computer Science, pages 63--74, Fischbachau, Germany, June 17--19 1991. Springer-Verlag.

....in S in and resulting in relations over a superscheme of S out 2 can be interpreted as a determinate query from S in to S out . The language CQL, however, is not complete with respect to the determinate queries. This can already be seen at the level of individual input output pairs of instances [1, 7]. Let Q be a determinate query, and suppose Q(I; J ) The only correspondence between I and J that can be derived from Definition 2.1 is that each automorphism in Aut(I) can be extended to an automorphism in Aut(J ) A stronger correspondence exists if Q can be computed by a CQL program, ....

M. Andries and J. Paredaens. A language for generic graph-transformations. In Graph-Theoretic Concepts in Computer Science, Proc. Int. Workshop WG 91, in Lecture Notes in Computer Science, 570, 63--74. Springer-Verlag, 1992.

....: new . 2 fa; bg = 3 Gamma Gamma Gamma Psi H H H H H Hj 0 R 1 Gamma Gamma Gamma Phi Phi Phi Phi Phi Phi 2 I oe a b Figure 2: A query not expressible in while new . There is an elegant necessary condition for a query to be computable by Datalog : new [AP92, dBGAG92] We present this condition, then show how it can be used to prove that the query in Example 7.2 is not expressible by Datalog : new . The condition involves inputoutput pairs of Datalog : new programs. For each input output pair hI; Ji, the condition requires a simple connection ....

M. Andries and J. Paredaens. A language for generic graph-transformations. In Proc. Int'l. Workshop WG 91, pages 63--74. Springer-Verlag, 1992.

....We denote by Aut(D) the automorphism group of D. The following notion of transformation as a database mapping expressing a restructuring operation or a query is inspired by Chandra and Harel [6] Abiteboul and Kanellakis [2] and Andries, Gyssens, Paredaens, Van den Bussche, and Van Gucht [17, 3]: Let N N . A transformation Q is a recursively enumerable relation Q inst(N ) Theta inst(N ) such that (i) Q is invariant under every permutation of S that is the identity on N [ f g; ii) Q is invariant under permutations of non attribute rows and non attribute columns in tables; iii) ....

M. Andries and J. Paredaens. On instancecompleteness of database query languages involving object creation. Journal of Computer and System Sciences. To appear. See also "A language for generic graph-transformations", Lecture Notes in Computer Science vol. 570, pp. 63--74.

.... s are new objects. This can be easy visualized using graphs: starting from a discrete graph containing two isolated A nodes a 1 ; a 2 , a C cycle of four new nodes b 1 ; b 4 is created such that two opposite b nodes are associated to a common a node through the B relation. It can be shown [3, 10, 29] that difficult queries are not expressible in IQL. The non completeness of IQL can be put in a more structured framework using the notion of instance with copies [3] Let S be a scheme, and let S 0 S. For each R 2 S Gamma S 0 , let CR be a relation name not in S for which a(CR) a(R) 1. ....

M. Andries and J. Paredaens. A language for generic graphtransformations. In Graph-Theoretic Concepts in Computer Science, volume 570 of Lecture Notes in Computer Science, pages 63--74. SpringerVerlag, 1992.

....term operations to denote both queries and data manipulations) In these models, it is investigated to what extent operations may be expressed in a purely graphical way. One may conclude from this research that the expressive power that may be obtained with pure graph based languages is unlimited [4]. However, one also gets the impression that some of this research overshoots its mark in the sense that the pure graphical formulation of an operation quite often looks even more complex than its textual equivalent. The solution to this problem which we present in this article, is to combine the ....

M. Andries and J. Paredaens. A Language for Generic Graph-Transformations. In G. Schmidt and R. Berghammer, editors, Proceedings of the 17th International Workshop on GraphTheoretic Concepts in Computer Science, volume 570 of Lecture Notes in Computer Science, pages 63--74, Berlin, 1992. Springer.

....25, 29, 34] In several of these models, it is investigated to what extent arbitrary data manipulations may be expressed in a purely graphical way. One can conclude from this research that there is no limit to the expressive power that may be obtained with pure graph based manipulation languages [4]. However, one also gets the impression that some of this research overshoots its mark in the sense that the pure graphical formulation of a query sometimes even looks more complex than its textual equivalent. The obvious solution to this problem is to try and combine the best of both worlds , ....

M. Andries and J. Paredaens. A Language for Generic Graph-Transformations. In Schmidt and Berghammer [31], pages 63--74.

....both object orientation and graphical interfaces are combined. The manipulation formalism consists of five elementary graphtransformation operations and a method construct, all of which are based on patternmatching. Since the model has been shown to be of significant expressive and modeling power [2, 3, 5], while at the same time its data model and manipulation formalism are defined using a limited number of very basic building blocks , GOOD may be regarded as a very general object oriented database model. The issue of this paper is to further elaborate the direct modeling power of the ....

Marc Andries and Jan Paredaens. A language for generic graph-transformations. In G. Schmidt and R. Berghammer, editors, Proceedings of the 17th International Workshop on Graph-Theoretic Concepts in Computer Science, volume 570 of Lecture Notes in Computer Science, pages 63--74, Berlin, 1992. Springer.

....turns down to graph rewriting. Hence, graph grammars [16] offer themselves as a natural framework for the manipulation of graph modeled data. The set of graph oriented database operations to be presented in this paper, is derived from the graph and object oriented database model GOOD [13, 17] In [3, 20], the graph grammar like language of GOOD was shown to satisfy the well established completeness and consistency criterion for database manipulation languages called BP completeness [6] Briefly, a language that satisfies this criterion is capable of expressing exactly all database transformations ....

M. Andries and J. Paredaens. A language for generic graph-transformations. In Schmidt and Berghammer

....up to renaming of new domain elements. Since IQL is a natural extension of the earlier languages of Abiteboul and Vianu [4, 5] complete in the sense of Chandra and Harel, it was expected at first that IQL would be complete for the determinate transformations. Surprisingly, this is not the case [3, 7]. In a sense that can be made precise, IQL lacks the ability to eliminate copies [3] One possible attitude to this problem is to view the incompleteness of IQL for the determinate transformations as a weakness of the language which should be remedied. In this vein, Abiteboul and Kanellakis ....

....expressible without copy elimination forms a natural subclass of the determinate transformations. We shall substantiate this thesis by providing a language independent characterization of the transformations expressible in IQL. A precursor to the present study is the work by Andries and Paredaens [7] in the context of the transformation language GOOD [19] which is essentially equivalent to IQL. Andries and Paredaens showed that a database J is the output of a GOOD program applied to a database I if and only if there exists an extension homomorphism from the group of automorphisms of I to the ....

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M. Andries and J. Paredaens. On instance-completeness of database query languages involving object creation. Journal of Computer and System Sciences. To appear. See also "A language for generic graphtransformations ", Lecture Notes in Computer Science vol. 570, pp. 63-- 74.

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