Kifer, M. and Wu, J. 'A logic for object oriented logic programming', in Proceedings of the 8th. ACM SIGACT/SIGMOD/SIGART Symposium on Principlea of Database Systems, Philadelphia, 1989, pp. 379-393.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....built up by function symbols denoting types of updates (insert, delete, modify) in such a way, that they admit tracing back the history of updates performed on each object. This approach is stimulated by F logic [KL89, KLW90] where general terms are used to denote objects (see also [CW89, KW89] and to control versions; however, updates are not considered in these works. VIDs have temporal characteristics, denoting different versions of an object during its update process. Each object version can be considered as a single stage corresponding to a certain time step of the entire ....

....we consider the method m to be set valued. Proceeding this way we do not have to consider consistency questions w.r.t. functionality of methods; moreover, we have a simple set concept in our language without any additional effort. In fact, it corresponds to the set semantics introduced in [CW89, KW89] Further it is worth to note, that our usage of function symbols does not enforce termination problems during bottom up evaluation, because we quantify over the set of all OIDs O, only. More precisely, for safe rules only a finite number of new versions can be derived during evaluation. Thus we ....

Michael Kifer and James Wu. A logic for object-oriented logic programming (Maier's O-Logic revisited). In Proc. ACM Symposium on Principles of Database Systems, pages 379 -- 393, 1989.

....COMPLEX [39] and Datalog t; 4] 2.2.1 Logics for Objects The approaches we classify in this subsection consider objects as terms and do not take into account state evolution of objects. These proposals originate from Maier s O logic [45] and evolve in Clogic [34] and the revised O logic [42]. These proposals are also strictly related to the LOGIN language [7] The final effort in this direction, which extends the previous ones, is Frame Logic (Flogic) 41] It extends previous works with higher order features to accommodate methods within complex terms. The motivations underlying ....

M. Kifer and J. Wu. A Logic for Object-Oriented Logic Programming (Maier's O-Logic Revisited) . In Proc. of the Eighth ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, pages 379 393, 1989.

....inheritance. From logic programming they inherit the concepts of unification and answer substitution and a strategy for deductive query processing. See e.g. 9] for a survey of the main approaches, beginning with O logic [20] and following with further developments such as extended O logic [11], F logic [10] and C logic [4] The field seems to have fallen dormant recently, subsumed to a large extent under the development of description logics (though the emphasis there is slightly different) For present purposes, C logic is particularly convenient. It provides a shorthand for FLBC ....

M. Kifer & J. Wu. A Logic for Object-Oriented Logic Programming (Maier's O-logic revisited). In Proceedings of the 8th ACM SICACT-SIGMOD-SIGART Symposium on the Principles of Database Systems, 1989.

....applicable at all. However, fixpoint iteration with subsumption can cope with this safety issue and derives the desired result. Example 4. 2 Consider a directed graph given by a relation edge: E[start node:X, end node:Y] in O Logic syntax and regard an OLogic program proposed by Kifer and Wu [KW89] to compute the set of paths between nodes in the graph. 3 path: add(E, nil) start X, end Y] edge: E[start node:X, end node:Y] path: add(E, P) start X, end Y] edge: E[start node:X, end node:Z] path: P[start node:Z, end node:Y] The object identifiers E and P ....

Michael Kifer and James Wu. A logic for object-oriented logic programming. In Proc. ACM SIGACT-SIGMOD Symp. on Principles of Database Systems, pages 379--393, Philadelphia, PA, Mar. 1989.

....transformations. We discuss determinacy, originally explored for the special case of queries, and show that some care must be taken when moving to arbitrary updates. We also compare the determinate approach to object creation of [AK89] as used in this paper, to the functional approach proposed in [KW89] There, newly created objects are interpreted as the result of functions applied to the existing objects. These functions are usually expressed as Skolem function terms, as is used in Logic Programming. We will show that the two approaches can be reconciled; in both approaches, object creation ....

.... PO ( new[id] name:john,age:40,address:new york] 6 9t 2 PO) t(name) john t(age) 40 t(address) new york We point out that the new operation is but a common denominator for many mechanisms for object creation considered in the literature [AV91a, AK89, GPVG90, HS91b, HY90, KW89, Zan89] An immediate consequence of genericity is that an object creating transformation must be non deterministic. For example, in Figure 1, the particular choice of ff and fi as new id s is not crucial: we could have taken and ffi as well. However, we can leave it to that, and restrict the ....

[Article contains additional citation context not shown here]

M. Kifer and J. Wu. A logic for object-oriented logic programming (Maier's O-logic revisited). In PODS [POD89], pages 379--393.

....queries. It should be noted that this completeness result is by no means specific to IQL, as IQL is equivalent to any minimal language that can express first order queries, object creation, and unbounded looping. Therefore, many other objectcreating query languages that have been considered (e.g. [11, 12, 13, 15, 18]) are essentially equivalent to IQL. Extending IQL to a complete language requires the introduction of an involved determinate copy elimination mechanism [2, 8] suggesting that the concept of determinate query is perhaps less natural than originally anticipated. From this viewpoint, restricting ....

M. Kifer and J. Wu. A logic for object-oriented logic programming (Maier's Ologic revisited). In Proc. 8th ACM Symp. Principles of Database Systems, 379--393. 1989.

....the tuple and the set constructor can be freely 32 nested in CO. For instance, a relation R with a tuple type T can be manipulated in ULCO by representing it as a class storing one object with type [R : fTg] Second, similarly to both IQL and ILOG and LOGRES (and differently from, for instance, [21]) in ULCO there is a clear separation between relations and instances, which make it possible to perform compile time type checking, with obvious advantages. Third, unlike LOGRES, the CO model do not support bags nor sequences. The reason for this is simply that we preferred to have a data model ....

M. Kifer and J. Wu. A logic for object-oriented logic programming (Maier's O-logic revisited). In Eigth ACM SIGACT SIGMOD SIGART Symp. on Principles of Database Systems, pages 379--393, 1989.

....is due to the great exibility that F logic o ers. It is credited to the uniform framework in which F logic deals with signatures and data. Though some condemn this exibility (cf. AK92] because it seems to come with the trade o that no strict typing is possible in earlier versions of F logic [Mai86, KW89, KL89]. In fact, that is not the case in the current version of F logic as presented in [KLW95] 3 EQUIVALENCE 9 In general we could de ne views based on queries, following the ideas in the work of dos Santos [dSAD94] on views in object oriented data models; but we refrain from doing so, and in ....

M. Kifer and J. Wu. A logic for object-oriented logic programming (Maier's O-logic revisited). In PODS89 [POD89], pages 389-393.

....for enlarging the range of applications that are considered. The logicprogramming aspect centers around the use of a (to a large extent) declarative language. Complicated procedural aspects as found in Prolog are not incorporated. Database languages based on resolution have been proposed, e.g. [35, 32]. We are not proposing a general purpose database programming language. For this, see, for instance, 20, 21] The goal is to obtain a simple to use, restricted database language that can be used to program a wide range of simple applications. Let us define some features of the goal ....

M. Kifer and J. Wu. A Logic for Object-Oriented Logic Programming (Maier's O-logic: Revisited). In Proc. ACM PODS, 1989.

....identifiers in correspondence to newly created objects. Object creation has been incorporated also in the rule based language ILOG (Hull and Yoshikawa [23] ILOG adopts a different (and more declarative) semantics for object creation, using Skolem functor terms as suggested in previous proposals [7, 33, 13, 27, 28]. In this paper we study the expressive power of a family of query languages with value invention in the context of relational databases. The languages are rule based, extend3 ing the syntax and semantics of datalog. The semantics of value invention is based on Skolem functors. Stratified ....

M. Kifer and J. Wu. A logic for object-oriented logic programming (Maier's Ologic revisited). In Eigth ACM SIGACT SIGMOD SIGART Symp. on Principles of Database Systems, pages 379--393, 1989.

....One of the initial attempts to formalise the notions underlying object oriented systems was O logic [80] Maier describes how objects, a class hierarchy and methods can be represented in a logic using object identity, labels and types. Two papers that followed from Maier s work were [36] and [66]. Chen and Warren [36] introduce a logic called C logic. Each formula in C logic can be transformed into an equivalent first order formula. Static type constraints and single valued labels are not built into the logic but can be added on top of it if needed. In [66] Kifer and Wu extended O logic ....

....from Maier s work were [36] and [66] Chen and Warren [36] introduce a logic called C logic. Each formula in C logic can be transformed into an equivalent first order formula. Static type constraints and single valued labels are not built into the logic but can be added on top of it if needed. In [66], Kifer and Wu extended O logic to incorporate sets and a way to deal with inconsistent information, and devised a sound and complete proof procedure. This work was extended in [65] by Kifer, Lausen, and Wu who define a logic called Frame Logic (or F logic) that accounts for most of the ....

[Article contains additional citation context not shown here]

M. Kifer and J. Wu. A logic for object-oriented logic programming (Maier's O-logic revisited). In Proc. 8th ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, Philadelphia, PA, March, 1989.

....algorithm is presented, in order to deal with built in inheritance. The typeinference mechanism is quite appealing, but the resolution based semantics seems hardly suitable to a database framework. On the other side, the so called alphabet logics (Maier [25] Chen and Warren [16] Kifer et al. [20, 22]) represent a strong effort directed to the development of a logic based framework for the management of objects and queries. In particular, F logic [20, 21] proposes a first order semantics and a higher order syntax, thus being able to perform interesting tasks such as schema browsing. Soundness ....

M. Kifer and J. Wu. A logic for object-oriented logic programming (Maier's Ologic revisited). In Eigth ACM SIGACT SIGMOD SIGART Symp. on Principles of Database Systems, pages 379--393, 1989.

.... this approach follows the research on non 1NF relations, in order to extend the data structures of logic programming with sets and complex terms [1, 14, 47, 74] Others attempt to formalize the basic object oriented concepts by developing a new logic to support various features of complex objects [8, 13, 37, 39, 49]. There is also another stream of work which approaches the problem from a programming language perspective. Here the aim is to extend the logic programming languages with some object oriented features such as methods and message passing [19, 25, 50, 75] These proposals are of less interest in ....

....while the semantics must be restricted enough to satisfy first orderness. A number of such object logics have been proposed. The first work, influenced by the terms of LOGIN [4] was Maier s O logic [49] which was later extended by a number of proposals, namely C logic [13] extended O logic [39], and F logic [37] From the object oriented world these logics acquire the notion of object identities, complex objects, a mechanism for object classification and a structure for property inheritance. From the logic programming world they absorb the concepts of unification, answer substitution ....

[Article contains additional citation context not shown here]

M. Kifer and J. Wu. A logic for object-oriented logic programming (Maier's O-logic revisited). In Proceedings of the 8th ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, 1989.

.... [13, 15] Ng and Subrahamanian investigated the theory of probabilistic reasoning based on another generalization of annotated logics[19] In addition, annotated logics have also been applied to the development of a declarative semantics for inheritance networks[11] and object oriented databases[14]. In view of the applicability of annotated logics to these di ering formalisms, it s necessary to study these logics carefully. As is known, it is necessary and important to establish the resolution theory in various non classical logics. Many works have been done in this eld, and there is no ....

Kifer, M., Wu, J., A Logic for Object Oriented Logic Programming, Proc. 8th ACM Symp. on Principles of Database Systems(1989), 379-393.

....is 8e 1 ; e 2 2 D 3 , e 1 Omega e 2 2 D 3 . The structure of the resulting element e = e 1 Omega e 2 is defined from the structure of e 1 and e 2 as follows: Let e 1 = id 1 ; v 1 ) and e 2 = id 2 ; v 2 ) Then e = id; v) is such that: ffl id = f(id 1 ; id 2 ) Here we follow the idea of [27] that the object id of the object generated from e 1 and e 2 should be a function of id 1 and id 2 . ffl attr(e) attr(e 1 ) attr(e 2 ) ffl 8A i 2 attr(e) e:A i = e 1 :A i [ e 2 :A i . Note that I 1 Omega I 1 j I 1 . This means that if I is obtained from the concatenation of I 1 and I 2 ....

Michael Kifer and James Wu. A logic for object-oriented logic programming (maier's ologic revisited). In Proceedings of the 1989 Symposium on Principles of Database Systems (PODS'89), Philadelphia, Pennsylvania, pages 379--393, March 1989.

....i only denotes the result of the application of an encoding function to o 1 ; on , which is invertible. The encoding function is not known by the user (who cannot distinguish complex oids from atomic ones either) A similar function which encodes oids, instead of referents, is defined in [KW89, KKS92, dS95b] Contrary to [KW89, KKS92, dS95b] a new identifier may occur in several distinct classes. The set of all identifiers, atomic and complex ones will be denoted by O. We now consider the concept of object referent, previously introduced in [dS95b] which extends the ODBS data ....

....application of an encoding function to o 1 ; on , which is invertible. The encoding function is not known by the user (who cannot distinguish complex oids from atomic ones either) A similar function which encodes oids, instead of referents, is defined in [KW89, KKS92, dS95b] Contrary to [KW89, KKS92, dS95b] a new identifier may occur in several distinct classes. The set of all identifiers, atomic and complex ones will be denoted by O. We now consider the concept of object referent, previously introduced in [dS95b] which extends the ODBS data model. In a traditional object model, ....

M. Kifer and J. Wu. A Logic for Object-Oriented Logic Programming (Maier's O-Logic Revisited). In Proc. ACM Symp. on Principles of Database Systems, 1989.

....is 8e 1 ; e 2 2 D 3 , e 1 Omega e 2 2 D 3 . The structure of the resulting element e = e 1 Omega e 2 is defined from the structure of e 1 and e 2 as follows: Let e 1 = id 1 ; v 1 ) and e 2 = id 2 ; v 2 ) Then e = id; v) is such that: ffl id = f(id 1 ; id 2 ) Here we follow the idea of [17] that the object id of the object generated from e 1 and e 2 should be a function of id 1 and id 2 . ffl attr(e) attr(e 1 ) attr(e 2 ) ffl 8A i 2 attr(e) e:A i = e 1 :A i [ e 2 :A i . Note that I 1 Omega I 1 j I 1 . This means that if I is obtained from the concatenation of I 1 and I 2 ....

M. Kifer and J. Wu. A logic for object-oriented logic programming (maier's o-logic revisited). In Proceedings of the 1989 Symposium on Principles of Database Systems (PODS'89), Philadelphia, Pennsylvania, pages 379--393, Mar. 1989.

....and compared with the algebra and the safe calculus. LDL has also been extended to deal with set valued attributes ( 17] see also the chapter of this volume) Another calculus for complex objects has been presented in [10] Recent research dealing with set values in logic based languages, such as [6, 2, 7, 25, 54, 62, 64, 71, 21] was carried out in the framework of object oriented models, but the impacts of set values are the same in an object or tuple component. Namely that the nesting of formulae into attribute positions in logical terms makes the language second order (at least syntactically) since this leads to ....

M. Kifer and J. Wu. A logic for object-oriented logic programming (Maier's O-Logic revisited). In Proc. ACM SIGACT/SIGMOD Symp. on Principles of Database Systems, pages 379--393, Philadelphia, March 1989. ACM.

....is 8e 1 ; e 2 2 D 3 , e 1 Omega e 2 2 D 3 . The structure of the resulting element e = e 1 Omega e 2 is defined from the structure of e 1 and e 2 as follows: Let e 1 = id 1 ; v 1 ) and e 2 = id 2 ; v 2 ) Then e = id; v) is such that: ffl id = f(id 1 ; id 2 ) Here we follow the idea of [12] that the object id of the object generated from e 1 and e 2 should be a function of id 1 and id 2 . ffl attr(e) attr(e 1 ) attr(e 2 ) ffl 8A i 2 attr(e) e:A i = e 1 :A i [ e 2 :A i . Note that I 1 Omega I 1 j I 1 . This means that if I is obtained from the concatenation of I 1 and I 2 ....

M. Kifer and J. Wu. A logic for object-oriented logic programming (Maier's o-logic revisited). In Proceedings of the 1989 Symposium on Principles of Database Systems (PODS'89), Philadelphia, Pennsylvania, pages 379--393, Mar. 1989.

....end; Figure 1: The schema Conference schema. only denotes the result of the application of an encoding function to o 1 ; o n , which is invertible. The encoding function is not known by the user who cannot distinguish complex oids from atomic ones either. The id function defined in [KW89, KKS92] is similar to our encoding function. Contrary to [KW89] new identifiers may occur in distinct classes. The set of all identifiers, atomic and complex ones will be denoted by O. We now consider the concept of object referent, previously introduced in [dS95b] which extends the ODBS ....

....the result of the application of an encoding function to o 1 ; o n , which is invertible. The encoding function is not known by the user who cannot distinguish complex oids from atomic ones either. The id function defined in [KW89, KKS92] is similar to our encoding function. Contrary to [KW89] new identifiers may occur in distinct classes. The set of all identifiers, atomic and complex ones will be denoted by O. We now consider the concept of object referent, previously introduced in [dS95b] which extends the ODBS data model. In a traditional object model, the object identified ....

M. Kifer and J. Wu. A Logic for Object-Oriented Logic Programming (Maier's O-Logic Revisited). In Proc. ACM Symp. on Principles of Database Systems, 1989.

.... , and behavioural issues including object specific operations (methods) and the encapsulation of object structures and these methods [13, 7, 9, 10] Recently, there have been several approaches in combining logic, rule based languages, and the structural part of an object oriented database model [6, 42, 32, 25] or even integrating methods and other behavioural aspects [1, 9, 23, 24] In this paper, we present a rule based language for the structural part of an object oriented database model. In comparison to the other approaches mentioned, there are some special features in our approach: ffl Since we ....

....tuples consisting of NAMEs and single HOBBIES are collected. These tuples are assigned to new objects not existing in the object base. These new objects are generated by the function gen Pers Hob in the head of the rule. The result is shown in Figure 11. 2 Note, that all the related approaches [6, 1, 21, 42, 32, 9, 10, 25, 23] also have an objectgenerating version of their rules. In IQL [6] for instance, new object identifiers are invented by introducing a new object variable which is not included in the body of the rule. The idea to generate new objects by functions is due to Kifer and Wu [25] it also appeared in ....

[Article contains additional citation context not shown here]

M. Kifer and J. Wu. A logic for object-oriented logic programming (Maier's O-Logic revisited). In Proc. ACM SIGACT/SIGMOD Symp. on Principles of Database Systems, pages 379--393. ACM New York, March 1989.

....IQL (Abiteboul and Kanellakis [2] and ILOG (Hull and Yoshikawa [13] which refer to data models in the traditional database sense. Other interesting ideas have also been proposed as extensions of logic programming languages (Maier [17] Ait Kaci and Nasr [3] Chen and Warren [12] Kifer et al. [15, 16]) In this framework, we have recently proposed IsaLog [5] a logic programming language over a model with (flat) classes and (flat) relations, with isa relationships among classes. A distinctive feature of IsaLog is the use of explicit This work was partially supported by MURST, within the ....

M. Kifer and J. Wu. A logic for object-oriented logic programming (Maier's Ologic revisited). In Eigth ACM SIGACT SIGMOD SIGART Symp. on Principles of Database Systems, pages 379--393, 1989.

....On the other hand, deductive databases rely on a flat data model and do not support data abstraction. It therefore can be expected that combining the two paradigms will pay off in a big way. A great number of attempts to combine the two approaches has been reported in the literature (e.g. [1, 2, 3, 14, 17, 18, 35, 58, 60, 68, 66, 73, 93, 11]) but, in our opinion, none was entirely successful. These approaches would either seriously restrict object structure and queries; or they would sacrifice declarativity by adding extra logical features; or they would omit important aspects of object oriented systems, such as typing and ....

....it gives no direct semantics to the important higher order constructs and it does not retain the spirit of objectoriented programming. In contrast, F logic represents higher order and object oriented concepts directly, both syntactically and semantically. This work builds upon our previous papers, [58, 55, 60], which in turn borrowed several important ideas from Maier s O logic [73] that, in its turn, was inspired by Ait Kaci s work on terms [7, 6] In [58, 60] we described a logic that adequately covered the structural aspect of complex objects but was short of capturing methods, types, and ....

[Article contains additional citation context not shown here]

M. Kifer and J. Wu. A logic for object-oriented logic programming (Maier's O-logic revisited). In ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems (PODS), pages 379--393, March 1989.

....hand, deductive databases normally use flat data model and do not support object identity and data abstraction. It therefore can be expected that combining the two paradigms will yield significant benefits. A number of attempts to combine the two approaches [AB88, AG87, BK89, BNST87, BNT88, CW89] KW89, Kup87, KV84, Mai86, RKS85] have been reported in the literature, but, in our opinion, none of them succeeds in meeting all of the above goals. These approaches either do not support object identity, or restrict the kinds of complex objects and queries one can use, or do not support inheritance, ....

....not true to the spirit of object oriented programming and frame based languages in AI. In contrast, we propose a logic which has an appearance of a higher order logic, but, unlike it, is tractable and has a natural direct first order semantics. More precisely, according to the classification of [CKW89] F logic has a higher order syntax and a first order semantics. A sound and complete proof procedure for F logic will be described in the full paper. This work is an extension of [KW89] which in turn was based on Maier s O logic [Mai86] In [KW89] a distinction between objects, classes, and ....

[Article contains additional citation context not shown here]

M. Kifer and J. Wu. A logic for object-oriented logic programming (Maier's O-logic revisited) . In ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems (PODS), pages 379--393, March 1989.

No context found.

Kifer, M. and Wu, J. 'A logic for object oriented logic programming', in Proceedings of the 8th. ACM SIGACT/SIGMOD/SIGART Symposium on Principlea of Database Systems, Philadelphia, 1989, pp. 379-393.

First 50 documents

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC