M. Kifer and G. Lausen. F-logic: A higher-order language for reasoning about objects, inheritance, and scheme. In Proceedings of ACM SIGMOD Conf. on Management of Data, volume 18, pages 134--146, Portland, Oregon, June 1989.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....omitted. Integrity constraints can be also used to optimize user queries. The theory of dependencies is discussed in [AbV85, AtD93, Mai83, PDG89, Tha91, Var88] The extension of this theory to other database model is developed in [AlT92, HuK87] Hul89, Jac82, Tha92] for semantic models and in [AbK91, BiD91, GKS91, Heu89, KiL89 ], STW91] for object oriented models. The book [Zal89] gives an impression on the algebraic treatment of dependencies. A survey on deductive databases is presented in [CGT91] Ull89] Further, the papers [Bid91, Bry89, Bry90] those cited in [GMN84] and in [Min88] cover several special topics. ....

M. Kifer and G. Lausen, F-logic: A higher-order language for reasoning about objects, inheritance and schema. Proc. ACM SIGMOD Conf. 1989, 134 -- 146.

....page s semantics than syntax based methods like keyword extraction. Dynamically generated pages are mapped to semantics by analyzing their query strings . The advantage of the KA architecture is that it provides independent logging of the full query strings which are expressions in F logic [13] and thus refer only to concepts and relations in the ontology. For details see [21] In a first approach, we have treated static and dynamic pages as a set, i.e. ##### ## ## #. In the following, this set will be represented as a feature vector, which contains 1 or a weight if a feature # ## is ....

M. Kifer and G. Lausen. F-logic: A higher-order language for reasoning about objects, inheritance, and scheme. In J. Clifford, B. G. Lindsay, and D. Maier, editors, Proceedings of the 1989 ACM SIGMOD International Conference on Management of Data, Portland, Oregon, May 31 - June 2, 1989, pages 134--146. ACM Press, 1989.

....for the languages proposed to query standard database schemas (e.g. SchemaSQL [38] XSQL [36] Noodle [46] Similar difficulties are encountered in logic based frameworks, whichhave been proposed for RDF manipulation. For instance, SiLRI [24] proposes some RDF reasoning mechanisms using F logic [37]. Although powerful, this approach does not capture the peculiarities of RDF: refinement of properties is not allowed (since slots are locally defined within classes) container values are not supported (since it relies on a pure object model) while resource descriptions having heterogeneous ....

M. Kifer and G. Lausen. F-logic: A higher-order language for reasoning about objects, inheritance, and scheme. In Proceedings of ACM SIGMOD Conf. on Management of Data,volume 18, pages 134--146, Portland, Oregon, June 1989.

....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 those approaches is the development of a logical framework for representing complex objects. Thus overcoming the absence of formal foundations for object oriented data ....

....Thus, a further step is needed to extend existing approaches to inheritance in logic languages with updates in order to model deductive objects with inheritance. Another possibility for grouping objects into classes is to use a logic which has two levels but it is, semantically, first order (see [41]) or through metaprogramming techniques. The second direction is not well organized as the first one because it addresses three different issues which are orthogonal to the object oriented paradigm and are orthogonal even among themselves. Nevertheless, they are very important for data management ....

M. Kifer and G. Lausen. F-Logic: A Higher-Order Language for Reasoning about Objects, Inheritance, and Schema. In Proc. of the ACM SIGMOD Lnt'l Conf. on Management of Data, pages 134 146, 1990.

....issue because it overcomes the dichotomy between data and operations of the relational model. Few proposals moreover, deal with behavioral inheritance and overriding. In addition to [ALUW93,LO91,McC88] these topics have been addressed in [BJ95,DT95,JL95] All these proposals extend F logic [KL90] or F logic variations) with behavioral inheritance. In F logic, indeed, only structural inheritance is directly captured. For behavioral inheritance, the non monotonic aspects introduced by the combination of overriding and dynamic binding are modeled only indirectly by means of an iterated ....

M. Kifer and G. Lausen. F-Logic: A Higher-Order Language for Reasoning about Objects, Inheritance, and Schema. In Proc. of the ACM SIGMOD Int'l Conf. on Management of Data, pages 134--146, 1990. E. Bertino, G. Guerrini, D. Montesi

....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 representations ....

M. Kifer & G. Lausen. F-logic: A Higher-Order Language for Reasoning about Objects, Inheritance and Scheme. In Proceedings of the 8th ACM SICACT-SIGMOD-SIGART Symposium on the Principles of Database Systems, 1989, pp. 134-146.

....correspondence predicates may have arbitrary arity, and also, because of data duplication, some n m correspondences may be introduced. 3 The Core Language In this section, we introduce the core language. This is in the style of rule based languages for objects, e.g. IQL [7] LDL [8] F logic [20] and more precisely, of MedMaker [25] The language we present in this section is tailored to correspondence derivation, and thus in some sense more limited. However, we will consider in a next section a powerful new feature. We assume the existence of three infinite sorts: a sort data var of ....

M. Kifer and G. Lausen. F-logic: A higher-order language for reasoning about objects. In sigmod, 1989.

....to deductive databases seems more promising than the opposite as it is significantly more difficult to provide object oriented languages with a formal foundation rather than extend deductive databases with objects. There has been various approaches for introducing objects in deductive databases [AK89, KL89, ALUW93]. In most of these approaches, the major issues of object identity, classes and inheritance are treated. Inheritance is a big advantage of object oriented systems. By declaring a class to be a subclass of another, information of the superclass is automatically inherited to the subclass. This ....

....issue rather than in conventional object oriented languages. The reason is that a definition should not necessarily override another that refer to the same predicate. It 1 may extend it. What is more is that it may extend it in various ways. Inheritance is examined in a variety of works. F Logic [KL89] framework addresses the issue of behavioral inheritance in deductive object oriented database query languages but fails to give it clear semantics. In [BJ95] an object oriented language loosely related to F Logic is presented. The language supports non monotonic behavioral inheritance and the ....

M. Kifer and G. Lausen. F-Logic: A higher--order language for reasoning about objects, inheritance, and scheme. In SIGMOD, pages 134--146, 1989.

.... Constraints are associated with a query which in turn becomes semantically optimized [2] Integrity constraints may be added to queries as functional equations [3] Type checking is performed at query compilation time [1] We apply the query optimization concept [2] to queries expressed in F logic [6]. We propose a query reformulation scheme by which a user issued query is reformulated into an equivalent and semantically rich query; the query incorporating rules and inheritances, and resolves conflicts between inherited and derived values. This paper is extended from the earlier work [5] In ....

....query. Evaluation priority for the reformulated queries is discussed in Section 5. Finally, Section 6 summarizes our work. 2 Preliminaries and Definitions We introduce the background knowledge used in F Logic in this section, leaving the syntactic and semantic details to the original paper [6]. The unique features of F logic which are essential to our work will be described. Before describing the features of F logic, the partial ordering theory [14] is introduced. Lattice A lattice is a formalism for an ordering of values based on their information content [14] The lattice in Figure ....

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Michael Kifer and George Lausen. F-logic: A higher-order language for reasoning about objects, inheritance, and scheme. In Proc. ACM SIGMOD Intl. Conf. on Management of Data, pages 134--146, Portland, Oregon, 1989.

....and complexity of query languages with object creation and duplicate elimination. This follows more or less the ideas of the IQL framework [3] The second one [12, 14, 15, 16, 56, 57] asks for the fundamental features of object oriented datamodels and their semantical foundations. The third group [4, 38] continues the line of research in which databases occur as theories de ned by classical logic programs. A view that is common in OODB research is that objects are abstractions of real world entities and should have an identity [8] This leads to a distinction between the concepts of values and ....

M. Kifer, G. Lausen. F-Logic: A Higher-order Language for Reasoning about Objects, Inheritance and Schema, in Proc. SIGMOD 1989, 134-146

....complexity of query languages with object creation and duplicate elimination. This follows 1 more or less the ideas of the IQL framework [3] The second one [12, 14, 15, 16, 54, 55] asks for the fundamental features of object oriented datamodels and their semantical foundations. The third group [4, 37] continues the line of research in which databases occur as theories de ned by logic programs. A view that is common in OODB research is that objects are abstractions of real world entities and should have an identity [8] This leads to a distinction between values and objects [11, 12] A value ....

M. Kifer, G. Lausen. F-Logic: A Higher-order Language for Reasoning about Objects, Inheritance and Schema, in Proc. SIGMOD 1989, 134-146

....starting point, since it does not include key concepts such as abstract types with methods and inheritance ) Also conspicuously missing is the notion of object identity. This was considered in an early model, the logical data model of [36] More recently it has gained a lot of attention, e.g. [5, 19, 33] There are a number of important issues not yet quite understood. These include for instance typing issues and object creation. The problem in object creation is the naming of the newly created object. In IQL [5] LOGRES [19] LOCO [37] or LLO [38] object identities come from a unique ....

....The problem in object creation is the naming of the newly created object. In IQL [5] LOGRES [19] LOCO [37] or LLO [38] object identities come from a unique infinite sort, and one new identifier is taken from that sort when necessary. In other formalisms (e.g. O logic of [39] or F logic of [33]) new objects are denoted using Skolem functions so the programmer directly controls their names. A number of interesting theoretical issues have resulted from the introduction of object identity (e.g. with respect to duplicate elimination [5] It should be noted that the use of created ....

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M. Kifer and G. Lausen. F-logic: A higher-order language for reasoning about objects. In sigmod, 1989.

....OODB H. M. Haav 2.2.1 Introduction The theory of lattices provides a natural basis for analysis of class and object hierarchies (or lattices) that occur in OO programming and database world. This has been recognized by several OO Programming and Database researchers during the few last years [17, 1, 7, 13, 32]. The purpose of the research is to clarify the meaning of class and object lattices used as underlying semantic structure for different query languages for 7 OODB. The report provides an analysis of lattice based languages. It also points to problems that arise when dealing with evolution of ....

....in OODB [13, 32] Languages supporting such facilities are mainly based on algebraic approach [32, 28] They have been developed on the basis of nested relational data model and its query languages. Logic based languages for complex objects use object lattices to give semantics for the formulas [17, 18, 1, 34]. Logical languages of complex objects support such important concepts of OO as object identity, inheritance and complex objects but do not consider methods modelling behaviour of objects in OO context. These languages are inspired by deductive database and logic programming research. Our ....

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Kifer M. and Lausen G. F-logic: A Higher-order Language for Reasoning about Objects, Inheritance, and Schema, In: Proceedings, ACM-SIGMOD Intl. Conf. on Management of Data, June 1989, pp. 134-146.

....databases by using concepts such as object identity, complex objects, classes, and inheritance. The integration of deductive and object oriented databases has received considerable attention over the past few years and several deductive object oriented database languages have been proposed [1, 2, 3, 4, 5, 6]. The theory of deductive databases without updates is well established and a declarative semantics is characterized as one of its most important features. Similar declarative semantics have also been given to object oriented database languages without updates. Updates are important database ....

.... in toy) toy : dept(manager henry)g M [3] f henry : empl(sal 2800; works in toy) tom : empl(sal 3000; works in toy; boss henry) tom : empl(sal 3000; works in toy; boss henry) salary : update; salary : update; toy : dept(manager henry) tom : highPaidEmplg M [4] = f tom : empl(sal 3300) tom : empl(sal 3300; works in toy; boss henry) henry : empl(sal 3280) henry : empl(sal 3280; works in toy) toy : dept(manager henry) tom : highPaidEmpl henry : highPaidEmplg M [5] f henry : empl(sal 3280; works in toy) Gammatom : ....

M. Kifer and G. Lausen. F-Logic: A higher-order language for reasoning about objects, inheritance, and schema. In Proc. ACM SIGMOD Intl. Conf. on Management of Data, pages 134--146, 1989.

....The preferred subtheories with partially ordered defaults as introduced in [Bre91] also apply a similiar prioritization scheme, but again they use syntactical instances of defaults (much simpler than the natural consequences of [Rya91] and do not respect specific object oriented issues. F logic [KL89] is an object oriented logic which has a monotonic inheritance mechanism contrasting with our non monotonic one. The idea is that the values are ordered in a lattice, so if there are two conflicting rules about the value of an attribute (e.g. one from the subclass and one from the superclass) ....

M. Kifer, G. Lausen: F-logic: A higher-order language for reasoning about objects, inheritance, and scheme. In J. Cli#ord, B. Lindsay, D. Maier (eds.), Proceedings of the 1989 ACM SIGMOD International Conference on the Management of Data, 134--146, 1989.

....monolithic wholes. The Telos implementation has not paid the same careful attention to efficiency of updates, but on the other hand it does support temporal reasoning, a full instance of hierarchy, and allows attributes as first class citizens. Interestingly enough, the database logic F logic [35] also treats individuals and attributes in a uniform way. Like Telos, it can express meta queries such as retrieve the set of all objects which represent the labels defined for a certain object . However, it does not support time and does not offer an instantiation dimension (instead, it treats ....

Kifer, M., and Lausen, G. F-Logic: A Higher-Order Language for Reasoning about Objects, Inheritance, and Scheme. In Proceedings of ACM SIGMOD International Conference on Management of Data (1989), pp. 134--146.

....as expressed in the logic s axioms and embedded in the calculus of procedure composition. Representation of Data Structures The tension between formal neatness and execution efficiency in the representation of data structures has arisen in several fields. In the field of logic programming, Kifer [30, 31] and Beeri [7] extend Horn clause logic to include more complex kinds of data than is available in Prolog, the first with objects and 13 the second with recursive record structures. These extensions do not provide the expressiveness of C, and neither researcher is concerned with execution ....

....is called a tuple, and can be written v 0 x 0 , v n x n or x 0 v 0 , x n v n . The values v 0 , v n need not be distinct. The relational signature t(t) of a tuple t is the set of variables to which 1 The relational algebra is described in many standard database texts, such as [30]. 66 it assigns values.Thus, the relational signature of v 0 x 0 , v n x n is x 0 , x n . Two tuples are disjoint if their relational signatures are disjoint as sets. The maximal relation M t for a signature t is the set of all tuples that have the signature t. A relation R is a ....

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Kifer, M., and Lausen, G., F-Logic: A Higher-Order Language for Reasoning about Objects, Inheritance, and Scheme, ACM SIGMOD Conf. on Mgt of Data, May 1989. pp. 134-146

....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 ....

Michael Kifer and Georg Lausen. F-logic: a higher order language for reasoning about objects, inheritance, and schema. In James Cliord, Bruce G. Lindsay, and David Maier, editors, Proceedings of the 1989 ACM SIGMOD International Conference on Management of Data, pages 134-146, 1989.

....structural part of OO database to represent the extended database model. Keywords: database semantics, object oriented databases, database modelling. 1 Introduction In spite of considerable research effort directed to the problems of the formalisation of object oriented (OO) database models [16, 3, 6, 10, 14, 23] in the last decade, there is still a lack of a strong theoretical background for OO databases. The main reason for this lies in the rich set of sophisticated data modelling constructs provided by OO database models [6] In this paper we focus on one aspect of the OO database models: a structural ....

....to be revised. Secondly, for the same reasons, the procedure used for the derivation of the value of a given class identifier presented by Definition 10, and Lemma 3, which presents the relationships between identifiers and values of objects, require some changes. Inheritance Similarly to F Logic [14, 15], two types of attribute which describe the state of a class need to be defined in order to be able to express the properties which are owned exclusively by the particular classes and those that are inherited by subclasses and instances. Firstly, the ordinary attributes which are inherited by all ....

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M. Kifer, G. Lausen, F-Logic: A Higher-Order Language for Reasoning about Objects, Inheritance, and Scheme, ACM SIGMOD 1989

....the languages and hence limits the power of the languages, e.g. the facility of using such a language for the view definition and manipulation, etc. The problems can be avoided in the first place by designing the DOOD language based on some kinds of higher order logics, e.g. the language F Logic [8,9] , which abolishes the traditional distinction between schema and instance of databases. However, this kind of languages are difficult to use for the normal users, and the implementations of these languages raise hard problems. In this paper, we are interested in the populations of derived ....

....an object of the derived entity type family. 3.1.1. OID generation There are two kinds of oid generation mechanisms have previously proposed for the rule created objects [7] 1) the oids are created by the values of facts [1,4,14] and (2) the oids are created by the proofs of the facts [8,9] . With the former mechanism, the superfluous identity is avoid in the first place, but it is argued that no 6 information of the proof of the fact is recorded in the oid. On the contrary, the second mechanism creates oids exactly according to the proofs of the facts, but it needs an operation, ....

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M.Kifer and G.Lausen, F-Logic: a Higher-Order Language for Reasoning about Objects, Inheritance and Sheme. Proc. ACM SIGMOD 1989. Portland, OR. April 1989

.... in linguistic grammar formalisms based on feature structure unification [Karttunen 84, Kasper and Rounds 86, Shieber 86, Johnson 88] Feature structures have also been used as a basis for incorporating object oriented concepts into logic programming language frameworks [Ait Kaci and Podelski 91, Kifer and Lausen 89, Yasukawa et al. 92] 3.2 Subsumption Atoms and all other values in Morphe are partially ordered according to a subsumption relation that corresponds to the relative specificity of information contained in the values. For example, int subsumes 1, string subsumes John , f Male Female g ....

Michael Kifer and G. Lausen. F-Logic: A Higher-Order Language for Reasoning about Objects. In Proceedings of the ACM SIGMOD Conference on Management of Data. ACM, 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 G. Lausen. F-logic: A higher order language for reasoning about objects, inheritance and scheme. In ACM SIGMOD International Conf. on Management of Data, pages 134--146, 1989.

....as an aid for a DATALOG reasoner, that cannot infer new descriptions on its own. In particular, in the AL log or CARIN frameworks there is no dialog between the components. DFL is an implemented hybrid of a description logic reasoner and a rule reasoner. The rule language is F(rames) Logic ([7, 8]) a rather expressive objectoriented language. Based on our previous work, where we proved that DLs are subsets of F logic ( 1] F Logic rules can include description formulae. Consequently, the integrated system gives rise to a rich dialog between its components, since the DL inferences can ....

M. Kifer and G. Lausen. F-logic: A higher-order language for reasoning about objects, inheritance, and scheme. In SIGMOD-89, 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 ....

....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 and completeness of the proposed resolution procedure were proven, along with an equivalent model theoretic semantics. The first attempt to develop a ....

M. Kifer and G. Lausen. F-logic: A higher order language for reasoning about objects, inheritance and scheme. In ACM SIGMOD International Conf. on Management of Data, pages 134--146, 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 ....

....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 and a strategy for ....

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M. Kifer and G. Lausen. F-logic: A higher-order language for reasoning about objects, inheritance, and scheme. In Proceedings of the 8th ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, pages 134--146, 1989.

....in [Jaffar and Lassez 87] in brackets ( In the example, the expression person : introduces a new type named person defined by the object descriptor on the right hand side of the colon. As in unification grammar formalisms [Shieber 86] and some logic based programming languages [Kifer and Lausen 89, Yokota and Yasukawa 92] Morphe does not make a distinction between classes and instances. Strictly speaking, every expression in Morphe is a type expression, and the execution of a Morphe program consists of finding the appropriate types for the variables, or in other words, solving the set of ....

Michael Kifer and Georg Lausen. F-Logic: A Higher-Order Language for Reasoning about Objects, Inheritance, and Scheme. In Proceedings of the ACM SIGMOD Conference on Management of Data. ACM, 1989.

....the object algebra of [S O90] and that of [HFW90] are the only other (algebraic) languages with object preserving operators. They also mention view support as one of the reasons for that semantics, but view updates have not yet been investigated. Some rule based languages, such as F logic [KL89] can specify object preserving as well as object generating operations, since there, OIds are available in the language. The type class separation, that can also be found in [Bee89, HFW90] is a consequence of object preservation: if both projections and selections are to preserve objects, and ....

M. Kifer and G. Lausen. F-Logic: A higher order language for reasoning about objects, inheritance, and scheme. In Proc. ACM SIGMOD Conf. on Management of Data, pages 134--146, Portland, OR, May 1989. ACM.

....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 ....

....nesting of formulae into attribute positions in logical terms makes the language second order (at least syntactically) since this leads to quantification over set values. In order to stay within first order calculus, such languages have to be given a first order semantical interpretation. F logic [62, 63] may be considered a state of the art language doing this. 3.5 Complex Objects By Complex Objects in the sense of [3] we mean data structures that are obtained by some arbitrary application of record and set constructors over a collection of base types (cf. Figure 1(c) That is, in contrast ....

M. Kifer and G. Lausen. F-Logic: A higher order language for reasoning about objects, inheritance, and scheme. In Proc. ACM SIGMOD Conf. on Management of Data, pages 134--146, Portland, OR, May 1989. ACM.

....conceptual schema of object oriented databases has, to our knowledge, not been addressed by recent database algebras, there are some query languages which include facilities to manipulate schema. In this respect, QAL was significantly influenced by F Logic as proposed by Kifer, Lausen and Wu in [24] and [26] F Logic is a declarative language which incorporates the constructs of object oriented data model and the frame based knowledge representation languages into logic. The possibility of querying data and schema portions of a database emerged from frame based knowledge representation ....

M. Kifer, G. Lausen, F-Logic: A Higher-Order Language for Reasoning about Objects, Inheritance, and Scheme, Proc. of the ACM Conf. on Management of Data, 1989, pp. 134-146.

....language [Cat94] for instance, does not allow explicit creation and manipulation of object id s) MSL and OEM can be seen as a form of first order logic. Indeed, we borrow many concepts from logic oriented languages such as datalog [Ull88, Ull89] HiLog [CKW93] O Logic [D. M86] and F Logic [KL89] HiLog first proposed under a logic framework the idea of mixing schema and data information. 9 It also demonstrated the reduction of nested structures into first order structures, a feature of OEM and MSL that will be illustrated in Appendix B. Nevertheless, we should not see MSL as a ....

....are modeled directly in datalog, they result in a large number of rules that are difficult to write and to process. We have also adopted from the area of logic and deductive databases the usage of object id s that indicate how the corresponding object was derived from source objects [KKS92, KL89] AK89] uses invented object id s for the manipulation and creation of sets, and as it also happens with MSL, they conclude that object id based set formation replaces the need for explicit grouping operators. Finally, ILOG [HY90] provides declarative creation and manipulation of object ....

M. Kifer and G. Lausen. F-logic: a higher-order language for reasoning about objects, inheritance, and scheme. In Proc. ACM SIGMOD Conference, pages 134--46, Portland, OR, June 1989.

....as our earlier example of a rebinding interpreter for metalogic did in Section 4. This approach preserves the declarative semantics but cannot deal easily with the identity of objects. Most approaches to object oriented programming in logic do not deal with updates at all. For example, F logic [20, 21] is intended as a foundation for object oriented ideas but update is left outside its scope. It is intended that F logic be combined with Transaction Logic to account for state change [21] An early proposal that bears some similarity to our rebinding mechanism is that of Chen and Warren using ....

Michael Kifer and Georg Lausen. F-Logic: A higher-order language for reasoning about objects, inheritance, and scheme. In James Clifford, Bruce Lindsay, and David Maier, editors, Proceedings of the ACM SIGMOD International Conference on the Management of Data, pages 134--146, Portland, Oregon, 1989.

....semantics for the underlying data model, ii) enhances productivity by encouraging high level database programming, iii) offers a hierarchical approach to implementation, and (iv) provides a basis for query optimization. 4 F Logic The proposal of Frame logic or F logic by Kifer and Lausen [14] characterizes the most fundamental departure from earlier works on deductive databases, as the new logic proposed incorporates such object oriented features as object identity and inheritance. Over the years, F Logic has been extended to encompass other OO features, such as the notions of complex ....

Kifer, M., and Lausen, G. F-logic: A higher order language for reasoning about objects, inheritance, and scheme. In Proceedings of the ACM SIGMOD Int. Conf. on Management of Data (Oregon, USA, 1989), ACM, pp. 134--146.

....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 logic [KL89] ....

.... [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 logic [KL89] Unfortunately, higher order unification problem is undecidable [Gol81] Most of existing deductive object oriented database languages make unnatural restrictions to avoid higher order logic in some way. Languages, such as COL, OIL, IQL, LOGRES separate schema from instance and use non logical ....

M. Kifer and G. Lausen. F-Logic: A Higher-Order Language for Reasoning about Objects, Inheritance, and Schema. In Proc. ACM SIGMOD Intl. Conf. on Management of Data, pages 134--146, 1989.

....The correspondence predicates may have arbitrary arity, and also, because of data duplication, some n m correspondences may be introduced. 4 The Core Language In this section, we develop the core language. This is in the style of rule based languages for objects, e.g. IQL [4] LDL [5] F logic [15] and more precisely, of MedMaker [19] Observe however that the language we present in this section is tailored to correspondence derivation, and thus in some sense more limited. However, we will consider in a next section a powerful new feature. We assume the existence of two infinite sorts: a ....

....R2L( 1; 1 0 ) r2l(F; T 3 r2l (F; This kind of deep trees is frequent in data exchange formats and it is important to be able to handle them. The correspondence rules that we described so far are essentially not new. Indeed, they are subsumed in some sense by previous proposals (e.g. [15, 10, 19]) This is because we are not interested in powerful query languages but in simple correspondence specifications that we can reuse when we consider translations. However, what we have seen above above is not quite powerful enough. It will have to be extended with particular operations on trees ....

M. Kifer and G. Lausen. F-logic: A higher-order language for reasoning about objects. In sigmod, 1989.

.... 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 are now living in a world of objects (and not in the world of values) the ....

....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 ....

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M. Kifer and G. Lausen. F-Logic: A higher order language for reasoning about objects, inheritance, and scheme. In Proc. ACM SIGMOD Conference on Management of Data, pages 134--146. ACM New York, May 1989.

....objectgenerating clauses to be able to represent new combinations of existing objects. If these clauses are evaluated n times, n objects would be generated for the same combination. To avoid these multiple objects, the new object identifiers are usually derived from the combination by a function [14, 11] so that a second evaluation of the object generating clause yields the same set of objects. So, these object identities are functionally dependent on the state of the object, instead of only determining it. The persistence of the generated objects is also questionable: they strongly depend on the ....

M. Kifer and G. Lausen. F-Logic: A higher order language for reasoning about objects, inheritance, and scheme. In Proc. ACM SIGMOD Conference on Management of Data, pages 134--146. ACM New York, May 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 G. Lausen. F-logic: A higher order language for reasoning about objects, inheritance and scheme. In ACM SIGMOD International Conf. on Management of Data, pages 134--146, 1989.

....by an efficient algorithm, rather than by expensive inference in expressive logics. Research in the formal foundation of object oriented and federated databases has focused on expressing the underlying relational schemas as an object schema based on some expressive first order or high order logics [3, 8, 10, 11]. Query translation is equivalent to inference in these logics, and hence is likely to be computationally expensive because efficient implementation techniques for these logics do not yet exist. Query translation has also been approached by using transformation rules specified in some expressive ....

....expressions and op is a path operator. The formula e1 op e2 , where op is of the form [Q1 ] Q2 ] evaluates to true if some (if Q1 = 9) or all (if Q1 = 8) elements in the value of e1 is in relationship to some (if Q2 = 9) or all (if Q2 = 8) elements in the value of e2 . For example, o:teaches[8] = 9]o:dept:courses computes the set of teachers who only teach courses in their own departments. A binding clause is of the form o: c, a AttributeOf c, or c SubclassOf c 0 , where o is either an object variable or an oid, a is either an attribute variable or the name of an attribute, and c; ....

[Article contains additional citation context not shown here]

M. Kifer and G. Lausen. F-logic: A higher-order language for reasoning about objects, inheritance, and scheme. In Proceedings of the ACM SIGMOD International Conference on Management of Data, pages 134--146, 1989.

....can be also used to optimize user queries. Bibliographical remarks The theory of dependencies is discussed in [AbV85, AtD93, Mai83, PDG89, Tha91, Var88] The extension of this theory to other database model is developed in [AlT92, HuK87] Hul89, Jac82, Tha92] for semantic models and in [AbK91, BiD91, GKS91, Heu89, KiL89 ], STW91] for object oriented models. The book [Zal89] gives an impression on the algebraic treatment of dependencies. A survey on deductive databases is presented in [CGT91] Ull89] Further, the papers [Bid91, Bry89, Bry90] those cited in [GMN84] and in [Min88] cover several special topics. ....

M. Kifer and G. Lausen, F-logic: A higher-order language for reasoning about objects, inheritance and schema. Proc. ACM SIGMOD Conf. 1989, 134 -- 146.

....as the natural next step to overcome these shortcomings (see for instance the proceedings of the DOOD conferences) We consider an extension of datalog with classes, methods, inheritance and a view mechanism and study method resolution for this language. The contribution is in the spirit of [AK89, KL89] a new (we believe important) step towards flexible and formal languages for databases. A major issue in object oriented languages is that of INRIA, 78153 Le Chesnay, France, Serge.Abiteboul inria.fr, Emmanuel.Waller inria.fr. Work partially supported by Esprit BRA Project Fide2. Fakultat ....

M. Kifer and G. Lausen. F-logic: A higher-order language for reasoning about objects, inheritance and scheme. In Proc. SIGMOD, 1989.

....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 ....

....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 inheritance. The earlier version of F logic reported in [55] 2 A PERSPECTIVE ON OBJECT ORIENTED VS. DECLARATIVE PROGRAMMING 2 was a step towards a higher order syntax. In particular, it supported querying database schema, and structural inheritance was built into the semantics. Nevertheless, this early version of F logic had several flaws. One of the ....

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M. Kifer and G. Lausen. F-logic: A higher-order language for reasoning about objects, inheritance and schema. In ACM SIGMOD Conference on Management of Data, pages 134--146, 1989. REFERENCES 97

....The preferred subtheories with partially ordered defaults as introduced in [Bre91] also apply a similiar prioritization scheme, but again they use syntactical instances of defaults (much simpler than the natural consequences of [Rya91] and do not respect specific object oriented issues. F logic [KL89] is an object oriented logic which has a monotonic inheritance mechanism contrasting with our non monotonic one. The idea is that the values are ordered in a lattice, so if there are two conflicting rules about the value of an attribute (e.g. one from the subclass and one from the superclass) ....

M. Kifer, G. Lausen: F-logic: A higher-order language for reasoning about objects, inheritance, and scheme. In J. Clifford, B. Lindsay, D. Maier (eds.), Proceedings of the 1989 ACM SIGMOD International Conference on the Management of Data, 134--146, 1989.

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M. Kifer and G. Lausen. F-logic: A higher-order language for reasoning about objects, inheritance, and scheme. In Proceedings of ACM SIGMOD Conf. on Management of Data, volume 18, pages 134--146, Portland, Oregon, June 1989.

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M. Kifer, G. Lausen: F-Logic - A Higher-Order Language for Reasoning about Objects, Inheritance, and Scheme, Freiburg, 1990

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Michael Kifer and Georg Lausen. F-Logic: A Higher-Order Language for Reasoning about Objects, Inheritance, and Scheme. In James Cli#ord, Bruce G. Lindsay, and David Maier, editors, Proceedings of the 1989 ACM SIGMOD International Conference on Management of Data, pages 134-- 146, Portland, Oregon, 31 May--2 June 1989.

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M. Kifer and G. Lausen. F-logic: A higher-order language for reasoning about objects, inheritance, and scheme. In Proceedings of ACM SIGMOD Conf. on Management of Data,volume 18, pages 134--146, Portland, Oregon, June 1989.

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Kifer, M., and Lausen, G. F-logic: a higher-order language for reasoning about objects, inheritance, and scheme. In International Conference on Management of Data and Symposium on Principles of Database Systems (1989), ACM Press, pp. 134-146.

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M. Kifer and G. Laussen. F-logic: A higher-order language for reasoning about objects, inheritance, and scheme. In Proceedings of ACM SIGMOD, pages 134--146, 1989.

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Kifer,M. and Lausen,G., F-Logic: a higher order language for reasoning about objects, inheritance and scheme. Proceedings of the ACM SIGMOD symposium on principles of database systems, SIGMOD RECORD, Vol.18, No.6, (1990).

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M. Kifer, G. Lausen. F-logic: A higher-order language for reasoning about objects, inheritance and Scheme. Proc. of SIGMOD Conf., 1989.

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