W. Chen and D. S. Warren. C-Logic for complex objects. In Proc. ACM Symposium on Principles of Database Systems, pages 369 -- 378, 1989.  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 ....

....a k , 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. ....

W. Chen and D. S. Warren. C-Logic for complex objects. In Proc. ACM Symposium on Principles of Database Systems, pages 369 -- 378, 1989.

....of such systems are LOGRES [30] 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. ....

W. Chen and D. S. Warren. C-Logic of Complex Objects. In Proc. of the Eighth ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, pages 369 378, 1989.

....and logic programming has attracted great interests. The objective is to gain the best of both approaches. Various methods of incorporating object oriented programming into Prolog have been discussed [5, 13, 14] Also, a number of novel languages have been proposed such as OOLP [3] C Logic [2], L O [11] Prolog [12] COMPLEX [4] LIFE [1] and some of them have been implemented. However, none of them support all important object oriented features. In this paper, we describe Pluto, an object oriented logic programming language that supports nearly all object oriented features in a ....

W. Chen and D.S. Warren. C-Logic for Complex Objects. In Proceedings of the ACM Symposium on Principles of Database Systems, pages 369-378, Philadelphia, Pennsylvania, 1989.

.... Among the efforts which have been focusing on the dynamic aspects of object oriented programming (i.e. change of state) we have mentioned [11, 17, 19, 29, 30, 31, 32] efforts which have been focusing on the static aspects (i.e. inheritance) of object oriented programming are described in [2, 9, 12, 16, 21, 33]. The framework presented here should provide a theoretical basis for the integration of these two traditions. 10, 28, 8] provide also extensions of Prolog in the direction of object oriented and distributed programming where formulae with multiple heads are allowed; some of the ideas ....

W. Chen and D.S. Warren. C-logic for complex objects. In Proc. of 8th ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, Philadelphia, Pa, U.S.A., 1989.

.... Among the efforts which have been focusing on the dynamic aspects of object oriented programming (i.e. change of state) we have mentioned [6, 12, 14, 22, 23, 24, 25] efforts which have been focusing on the static aspects (i.e. inheritance) of object oriented programming are described in [1, 4, 7, 11, 26]. The framework presented here should provide a theoretical basis for the integration of these two traditions. 5] provides also an extension of Prolog in the direction of object oriented programming where clauses with multiple heads are allowed; some of the ideas characterizing this approach are ....

W. Chen and D.S. Warren. C-logic for complex objects. In Proc. of 8th ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, Philadelphia, Pa, U.S.A., 1989.

....Section 6 closes with some concluding remarks. Related Work. To our knowledge, none of the existing dood languages supports WFS: For several early logics introducing OO features like object id s, types classes, or set values, e.g. O Logic [Mai86] and its relatives presented in [KW93] or [CW89] C Logic) or ILOG [HY90] the semantics of programs is reduced to the semantics of first order logic programs via program transformations, but these approaches lack some typical OO features. COL (complex object language) AG91] extends Datalog by structured values and set constructors, without ....

W. Chen and D. S. Warren. C-Logic for complex objects. In Proc. ACM Symposium on Principles of Database Systems, pages 369 -- 378, 1989.

.... paradigms and data models (logic programming, complex objects, functional models, semantic models) In particular, much work has been devoted, on one hand, to the formalization of novel data models (e.g. 4, 20, 22] and on the other hand to the design of advanced database query languages (e.g. [3, 5, 14, 16, 26]) and to the development of efficient query answering techniques (e.g. 11, 12, 27] Less attention has been deserved to the problem of defining update languages for advanced database environments, although an adequate support of the update activity is a very important task that any database ....

W. Chen and D.S. Warren. C-logic for complex objects. In Eigth ACM SIGACT SIGMOD SIGART Symp. on Principles of Database Systems, pages 369--378, 1989. 41

....developed to exploit them, the analysis of success and context conditions, along with unification and substitution factoring may lay the foundation for global analysis and compilation of tabled code. Language constructs involving so called object orientation are currently popular. A C Logic [15] interface has been implemented for XSB by K. Sagonas which offers support for viewing relations as objects. A more ambitious language, F Logic [37] offers support for all commonly recognized object oriented capabilities. Like C Logic, F Logic is reducible to first order logic, and its ....

W. Chen and D.S. Warren. C-logic of complex objects. In Proc. of 8th PODS, pages 369 -- 378, 1989.

....4.1, the last of all benefit periods before . Thus, we need to refer to the set of all those benefit period tokens that are Before . Coping with the notion of set requires higher order expressiveness. Some research has been done on extending first order languages in this direction [28, 26, 1, 11, 24, 12]. We restrict the development here to the context of a token based approach where the set notion is used to specify sets of temporal tokens that satisfy a certain condition. The syntax we propose is as follows 16 : token set( temporal atom] where temporal atom can be either a token atom, ....

W. Chen and D. Warren. C-logic of complex objects. In Proc. of 8th ACM-SIGACTSIGMOD -SIGART Symposium of Principles of Database Systems, 1989.

....query languages. In the past few years, a lot of efforts have been made to integrate deductive and object oriented databases to gain the best of the two approaches. A number of deductive object oriented database languages have been proposed, such as O logic [31] revised O logic [25] C logic [19], IQL [5] IQL2[1] F logic [24] LOGRES [16] LLO [30] LOL [14] Datalog method [6] DLT [10] Gulog [20] Coral [36] and Rock Roll [12] However, none of these proposals have achieved the objectives of providing the necessary expressive power for data and knowledge applications in a ....

W. Chen and D. S. Warren. C-logic for complex objects. In Proc. ACM Symp. on Principles of Database Systems, pp. 369--378, Philadelphia, Pennsylvania (1989).

....in ROL can be achieved not only by object identity but also by using rules. ROL also supports other important object database features such as complex objects, classes, class hierarchies, multiple inheritance with overriding and blocking. 6 LIU Unlike O logic [32] revised O logic [26] C logic [16], and F logic [24] which provide no direct support for relations, non first normal form relations are directly representable in ROL using functor objects, and traditional deductive database languages such as Datalog and LDL (without grouping) are subsumed as special cases in ROL. Languages such as ....

....tuples, but functor objects can be used to indirectly represent tuples in ROL. Besides, rule defined functor objects correspond to rule generated object identifiers as in O logic [32] F logic [24] IQL [6] and LOGRES [12] In Iris [19] Jasmine [21] O logic [32] revised O logic [26] C logic [16], and Flogic [24] values, object identifiers and or functor objects are objects, but sets are not objects and functor objects if present cannot contain sets. Our notion of object is more general. Objects have attributes through which they are related to each other. In ROL, not only object ....

W. Chen and D. S. Warren. C-logic for complex objects. In Proceedings of the ACM Symposium on Principles of Database Systems, pages 369--378, Philadelphia, Pennsylvania, 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 ....

W. Chen and D.S. Warren. C-logic for complex objects. In Eigth ACM SIGACT SIGMOD SIGART Symp. on Principles of Database Systems, pages 369--378, 1989.

....query languages. In the past few years, a lot of efforts have been made to integrate deductive and object oriented databases to gain the best of the two approaches. A number of deductive object oriented database languages have been proposed, such as O logic [29] revised O logic [22] C logic [17], IQL [4] IQL2[1] F logic [21] LOGRES [14] LLO [28] LOL [13] Datalog method [5] DLT [9] Gulog [19] and Rock Roll [10] Object identity is useful for supporting object sharing and update management. However, using object identifiers for every object is burdensome even in pure ....

W. Chen and D. S. Warren. C-logic for complex objects. In Proc. ACM Symp. on Principles of Database Systems, pages 369--378, Philadelphia, Pennsylvania, 1989.

....from deductive approaches, and object identity, complex objects, classes, class hierarchy, property inheritance with overriding and schema from object oriented approach. A number of deductive object oriented database languages have been proposed, such as O logic [17] revised O logic [11] C logic [8], IQL [2] IQL2[1] Flogic [10] LOGRES [7] LLO [16] LOL [6] CORAL [19] Datalog method [3] DLT [4] Gulog [9] and Rock Roll [5] However, most of these languages stay at the theoretical level. Some of them, such as F logic, are technically too complicated and it is far from clear how ....

W. Chen and D.S. Warren. C-Logic for Complex Objects. In Proceedings of the ACM Symposium on Principles of Database Systems, pages 369-378, Philadelphia, Pennsylvania, 1989.

....a relation. 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 ....

....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 to incorporate sets ....

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W. Chen and D. Warren. C-Logic of complex objects. In Proc. 8th ACM SIGACTSIGMOD -SIGART Symposium on Principles of Database Systems, Philadelphia, PA, March, 1989.

....ad hoc unification 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 ....

W. Chen and D.S. Warren. C-logic for complex objects. In Eigth ACM SIGACT SIGMOD SIGART Symp. on Principles of Database Systems, pages 369--378, 1989.

....query languages. In the past few years, a lot of efforts have been made to integrate deductive and object oriented databases to gain the best of the two approaches. A number of deductive object oriented database languages have been proposed, such as O logic [20] revised O logic [15] C logic [11], IQL [3] IQL2 [1] Flogic [14] LOGRES [9] LLO [19] LOL [8] DLT [5] Gulog [12] and Rock Roll [6] However, none of these proposals have achieved the objective of providing the necessary expressive power for data and knowledge applications in a declarative fashion with a well defined ....

W. Chen and D. S. Warren. C-logic for complex objects. In Proc. ACM Symp. on Principles of Database Systems, pages 369--378, Philadelphia, Pennsylvania, 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 ....

....manipulate such concepts 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, ....

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W. Chen and D. Warren. C-logic of complex objects. In Proceedings of the 8th ACM SIGACT-SIGMOD-SIGART Symposium on the Principles of Database Systems, 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 ....

....once a handle to that object is obtained. This handle is usually referred to as physical object identity an implementational notion that also has a conceptual counterpart, which we call logical object identity. Logical oid s were introduced in [58, 60] and, subsequently, were utilized in [35, 16] and other works. The concept of object identity was widely discussed in database literature. An early attempt to bring this notion into the fold of a logical theory was reported by Maier [73] Reflecting on this work, Ullman [102] concluded that the very concept of object identity is incompatible ....

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W. Chen and D.S. Warren. C-logic for complex objects. In ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems (PODS), pages 369--378, March 1989.

....language. 1487 1 Introduction The integration of deductive and object oriented database systems has received considerable attention over the past few years. A number of deductive object oriented database languages have been reported, such as O logic [Mai86] revised O logic [KW93] C Logic [CW89] F logic [KL89, KLW90] COL [AG91] OIL [Zan89] IQL [AK89, Abi90] LOGRES [CCCR 90] LLO [LO91] LOL [BM92] L O [McC92] and Gulog [DT93] To deal with complex objects naturally and directly, proper notions are needed for sets, schema and inheritance, which normally lead to higher order ....

W. Chen and D.S. Warren. C-Logic for Complex Objects. In Proc. ACM Symp. on Principles of Database Systems, pages 369--378, 1989.

....other 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 ....

....phil. Clauses (2) through (4) present similar information about mary, john, and sally. Note that the friends attribute in mary s record is set valued , which is syntactically expressed by means of the set constructor f g. Our syntax is that from [Mai86, KW89] with some embellishments from [CW89] Clauses (5) 6) and (7) provide general information about classes faculty , students, and empl, such as that faculty are normally supervised by faculty and are middle aged, students are normally young , etc. Clause (8) is a rule stating that employee s supervisor is the manager of the ....

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W. Chen and D. S. Warren. C-Logic for complex objects. In ACM SIGACT-SIGMODSIGART Symposium on Principles of Database Systems (PODS), pages 369 -- 378, 1989.

....with respect to the entailment relation of the corresponding modal framework. The proposed semantics represents to our knowledge the first attempt to capture a truly logical semantics of encapsulation in deductive object oriented languages. 1 Introduction There have been several attempts [9, 10, 1, 5, 11, 2, 16] at combining logic programming with object oriented concepts like object identity, complex objects, methods, encapsulation, signatures, inheritance, etc. in a clean mathematical framework. Most of the approaches either fall short of capturing the essential set of properties of object orientation ....

W. Chen and D. S. Warren. C-Logic for Complex Objects. In ACM SIGMOD Conference on Management of Data, 1989.

....are the languages 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 ....

W. Chen and D.S. Warren. C-logic for complex objects. In Eigth ACM SIGACT SIGMOD SIGART Symp. on Principles of Database Systems, pages 369--378, 1989.

....DATALOG [10] seen as the logic programming language underlying DRDBs, is progressively extended with complex typed terms, object identity, inheritance and so on. 2. redesigning the deductive language this characterizes the work that resulted in the family composed of the C O F logic languages [11, 19, 21]. Here, no data model is assumed in the background, rather there is the intention of expressing directly at the logic language level all the features deemed necessary to model a domain in an object oriented style. 3. redesigning the data model this characterizes our work [16, 14] Here, the ....

Weidong Chen and David S. Warren. C-Logic of Complex Objects. In Proceedings of the 8th ACM SIGACTSIGMOD -SIGART Symposium on Principles of Database Systems, pages 369--378, Philadelphia,PA, March 1989. ACM Press.

....since the latter has a first order semantics, and the translation of paradoxical LDL rules yields rather benign HiLog programs. To conclude this comparison, we mention that the alternative semantics for sets in LDL and COL described above is in the same spirit as the semantics described in C logic [12] and O logic [28] although the latter are first order (object oriented) languages. It appears thus, that higher orderness of the syntax of HiLog is inessential in order to simulate sets. However, it is essential for other applications described earlier. It seems like an interesting observation, ....

....philosophy behind logical languages can in some cases eliminate the need for higher orderness either in semantics, or in syntax, or in both. Another promising application of HiLog in the database field is its use as an implementation vehicle for object oriented languages recently proposed in [12, 28, 24, 25]. C logic [12] is the simplest of the three; it supports complex objects, object ids, sets, and classes. For instance, the hobby example discussed earlier can be represented in C logic as follows: 9 In our opinion, the above discussion suggests that capturing the semantics of grouping ....

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Chen, W. and Warren, D.S. [1989] C-logic for Complex Objects, in Proceedings of the ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, March 1989, pp. 369--378.

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