E. Bertino, M. Martelli, and D. Montesi. Modeling Database Updates with Constraint Logic Programming. In U. W. Lipeck and B. Thalheim, editors, Fourth Int'l Workshop on Foundation of Models and Languages for Data and Objects, pages 42--53, 1992.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....hence wrt F 3 ) Since the system preserves the compositional semantics, it can be used for the modular transformation of programs. Update specifications. In the context of languages for deductive databases, updates are important programming facilities (similar to assert and retract of PROLOG) [4] defines a constraint logic language ECD with elementary updates to model the dynamic behavior of database systems. The semantics of ECD is obtained by using an extension of our constructions. Since updates in ECD are expressed by means of constraints, such a semantics provides a declarative ....

E. Bertino, M. Martelli, and D. Montesi. Modeling Database Updates with Constraint Logic Programming. In Proc. Fourth Int'l Work. on Foundations of Models and Languages for Data and Objects, 1992.

....on top of some primitive (predefined) method (e.g. updating variables or allocating memory) In the general case, the extensional components that can Main.tex; 4 08 1998; 4:12; p. 8 9 be updated by methods might be functions (as happens in evolving algebras [31] or relations (as in Update Datalog [11]) Let us turn to consider the semantics of Circle. Formally, we describe the operational interface of the module by the following object signature (Def.6 ) O Sigma C = sorts real ; bool ; posReal opns x ; y : real , r : posReal methods grow : posReal ) isOrigIn: bool , move: real real ....

....with intensional components, rejecting extensional dynamic and intensional static components. Note that both these kinds of components are sensible: methods that can be dynamically updated (see, e.g. the object calculus defined in [1] are extensional dynamic components, whereas queries in [11] are intensional static components. Note, however, that, whereas the latter form of components could be easily introduced, extensional dynamic components do not fit in our model. Using the static framework AlgSig; PAlg , we can model the states of the Circle module as partial algebras. If the ....

Bertino, E., M. Martelli, and D. Montesi: 1992, `Modeling Database Updates with Constraint Logic Programming'. In: U. W. Lipeck and B. Thalheim (eds.): Fourth Int'l Workshop on Foundation of Models and Languages for Data and Objects. pp. 42--53.

....emerged: to unify the different paradigms under a common semantics (often by using compilative techniques) 7, 20, 23, 27, 33] or to integrate specific semantics [11] In this paper, we follow the latter approach. We present an integration of deductive and active databases by extending U Datalog [5, 22] with a support for active rules in the style of the PARK semantics [14] we call the resulting language Active U Datalog. U Datalog is an extension to Datalog supporting declarative specification of updates based on a nonimmediate update semantics. U Datalog is well suited to such an extension ....

....The main condition is, obviously, the absence of active rules in the Active U Datalog program. To this end, we first give a formal description of U Datalog syntax and semantics [22] 5. 1 U Datalog as CLP(AD) An U Datalog program can be viewed as an instance of a CLP schema [16] called CLP(AD) [5]. We consider a fixed ( Pi; Sigma; V ) language. Pi is partitioned into four sets of symbols: Pi e , Pi i , Pi u defined as in section 3, and the binding predicate symbol Pi b = f=g. Definition 19 (U Datalog syntax) An U Datalog program (or database) P = IDB[EDB consists of the ....

E. Bertino and D. Montesi. Modeling database updates with constraint logic programming. In U. W. Lipeck and B. Thalheim, editors, Proc. of the Fourth International Workshop on Foundations of Models and Languages for Data and Objects, pages 120--132, 1992.

....different from the language used for describing rules, making transaction optimization difficult [13] To overcome these drawbacks we use a new approach to integrate declarative query language and updates, modeling transactions. The language we use is U Datalog. The basic idea of U Datalog [5, 20] is that (extensional) updates are not executed as soon as they are evaluated. Rather, they are collected and are executed only at the end of the query answering process. Updates, due to the non immediate semantics, are expressed in a declarative way by using constraints, that is p(a) states that ....

.... with updates in the head does not allow the transmission of runtime parameters (for such languages only a bottom up computational model is allowed) ii) Updates with non immediate semantics in rule body result in a language which fits nicely into the formal setting of constraint logic programming [5] and for which both a bottom up and a top down computational models, proved equivalent, can be defined. The execution model of U Datalog consists of two phases, the marking phase and the update phase. The first phase collects the updates found during the evaluation process, without, however, ....

E. Bertino, M. Martelli, and D. Montesi. Modeling Database Updates with Constraint Logic Programming. In U. W. Lipeck and B. Thalheim, editors, Proc. Fourth Int'l Work. on Foundations of Models and Languages for Data and Objects, pages 120--132, 1992.

....play an important role in modeling dynamic behaviors in database systems [1, 24] Various languages have been proposed for specifying database updates. Examples include procedural languages [4] Datalog extensions with inflationary semantics [3] Datalog extensions with top down computation [7, 25], and extensions of first order logic [9, 12, 30] Both queries and updates can be viewed as database transformations in the sense that queries define relations that represent answers and updates define relations that represent a new database state. The power of database languages for expressing ....

....in the sense that queries define relations that represent answers and updates define relations that represent a new database state. The power of database languages for expressing such transformations is well understood [4, 3] Although Datalog extensions have been proposed for updates [3, 7, 25], they are not integrated with the declarative semantics of logic programs with negation. The latter extend relational queries and provide a powerful recursive query language. There has been significant progress in understanding the declarative semantics of logic programs and processing queries ....

[Article contains additional citation context not shown here]

Bertino, E., Martelli, M., and Montesi, D. Modeling database updates with constraint logic programming. In Proceedings of the Deductive Database Workshop at Joint International Conference and Symposium on Logic Programming, 1992.

....a formal behavior and also a computational model. Note that we consider an extension to Datalog modeling updates and transactions. The language in which our modules are expressed is in fact Update Datalog (U Datalog) an extension of Datalog which allows the specification of updates in rule bodies [18]. The relevant characteristic of U Datalog is that updates are not executed as soon as they are evaluated, rather they are collected in a set and executed altogether at the end of the refutation process, if this process succeeds and the set is ground and consistent (i.e. it does not contain ....

E. Bertino, M. Martelli, and D. Montesi. Modeling Database Updates with Constraint Logic Programming. In U. W. Lipeck and B. Thaihelm, editors, Fourth Lnt'l Work, hop on Foundation of Model and Languages for Data and Objects, pages 42 53, 1992.

....in terms of constraint logic programming (CLP) 36] one of the most relevant research directions in the logic programming area. CLP integrates twoof the most interesting programming paradigms, namely constraint and logic programming. Updates in rule bodies are specified through constraints [12]. Therefore, our language inherits the formal setting of CLP, in a similar way as Datalog inherits the formal setting of logic programming. The remainder of this paper is organized as follows. Section 2 introduces the basic notions of deductive databases and reviews related works. Section 3 ....

E. Bertino, M. Martelli, and D. Montesi. Modeling Database Updates with Constraint Logic Programming. In U. W. Lipeck and B. Thalheim, editors, Proc. Fourth Int'l Work. on Foundations of Models and Languages for Data and Objects, pp. 120--132, Dagstuhl, 1992.

....computation. In the first phase updates are collected and their consistency is checked. In the second phase the updates are executed together modeling a transactional behavior. The formal semantics is given in [8] while two optimization techniques are presented in [7] We refer the reader to [9] for additional details. The computation model chosen for the U Datalog interpreter is based on a bottom up strategy. This is very important for two reasons: in database context the answer to a query is a set, hence the bottom up strategy is the most appropriate; however, Datalog with updates in ....

....as soon as they are evaluated, that is, they are executed as side effect of the derivation process. In this section we recall some basic notions on the syntax and the semantics of U Datalog, which are defined by means of an instance of constraint logic programming schema (CLP) 12] called CLP (AD) [9]. Updates in U Datalog are in rule bodies. In addition we consider also bindings in rule bodies which are defined by means of a set of equations (this is related to the fact that U Datalog is an instance of CLP) Updates to base relations are expressed as a set of special atoms prefixed by Sigma. ....

E. Bertino, M. Martelli, and D. Montesi. Modeling Database Updates with Constraint Logic Programming. In U. W. Lipeck and B. Thalheim, editors, Proc. Fourth Int'l Work. on Foundations of Models and Languages for Data and Objects, pages 120--132, 1992.

....databases with updates in rule bodies do not allow to use bottom up execution model. This is due to the introduction of control in rule bodies induced by update sequences. However, bottom up strategies are very important due to the set oriented query answering process of database systems. In [7] an extended rule language was proposed that allows to accommodate updates and support transactions while avoiding the above drawback. In this paper we present an extension of the Magic Sets transformation and the Semi Naive strategy for efficiently evaluating the extended rule language. This new ....

....modified are determined by issuing queries. Moreover, updates should be collected into atomic execution units which are executed in a all or nothing style, that is, as transactions. Transactions are a crucial functionality, since data integrity is a major requirement for database applications. In [7] a language based on a new approach to smoothly integrate a declarative query language with an update language was introduced. Such integration is achieved by taking into account the transactional behavior. The resulting language, called U Datalog, provides both update and query capabilities and ....

[Article contains additional citation context not shown here]

E. Bertino, M. Martelli, and D. Montesi. Modeling Database Updates with Constraint Logic Programming. In U. W. Lipeck and B. Thalheim, editors, Proc. Fourth Int'l Work. on Foundations of Models and Languages for Data and Objects, pages 120--132, 1992.

....However, the semantics of rules containing updates is difficult to define. Indeed, in most proposals of rule languages with updates, the semantics of rules is dependent on the evaluation order of the rules. Therefore, those languages are not fully declarative. A recent proposal of a rule language [5] overcomes the above problem . This language provides updates in rules by providing at the same time a declarative semantics. In this language a rule has the form . In the above rule . and . represent conjunctions of insertions and deletions respectively. They are also in ....

....By contrast in DLP and , updates are executed as soon as they are evaluated, that is, they are executed as side effect of the derivation process. We recall now some basic notions on U Datalog. It is defined by means of an instance of constraint logic programming schema (CLP) 11] called ( [5]. In the following we will assume the reader familiar with logic programming [3] and with CLP. Updates in U Datalog are in rule bodies. In addition we consider also bindings in rule bodies which are defined by means of a set of equations (this is related to the fact that U Datalog is an instance ....

E. Bertino, M. Martelli, and D. Montesi. Modeling Database Updates with Constraint Logic Programming. In U. W. Lipeck and B. Thalheim, editors, , pages 42--53, 1992.

....to the formal model underlying deductive databases, which provides a formal behavior and also a computational model. Note that we will consider an extension to Datalog considering updates and transactions. The language in which our modules are expressed is in fact Update Datalog (U Datalog) [10], an extension of Datalog which allows the specification of updates in rule bodies. The relevant characteristic of U Datalog is that updates are not executed as soon as they are evaluated, rather they are collected in a set and executed altogether at the end of the refutation process, if this ....

E. Bertino, M. Martelli, D. Montesi. Modeling Database Updates with Constraint Logic Programming. In Proc. 4th Int'l Workshop on Foundations of Models and Languages for Data and Objects: Modeling Database Dynamics, 1992.

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E. Bertino, M. Martelli, and D. Montesi. Modeling Database Updates with Constraint Logic Programming. In U. W. Lipeck and B. Thalheim, editors, Fourth Int'l Workshop on Foundation of Models and Languages for Data and Objects, pages 42--53, 1992.

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