Serge Abiteboul and Stephane Grumbach. COL: a logic-based language for complex objects. In Francois Bancilhon and Peter Buneman, editors, Advances in Database Programming Languages, pages 347-374. ACM Press, New York, 1990. 10  Home/Search   Document Not in Database   Summary   Related Articles   Check

....a Query Language for Object oriented Databases The first approach in this direction has been Datalog extension to deal with structured objects, defining query languages whose corresponding data model is not a 1NF relational model, rather an extended relational model. COL (Complex Object Laguage) [2] is an example of a deductive language for value based models supporting structured objects, even it is not an object based language. COL is a Datalog extension allowing the manipulation of structured values obtained using tuple and set constructors. Besides relations, base and derived ones, the ....

S. Abiteboul and S. Grumbach. COL: A Logic Based Language for Complex Objects. In F. Bancilhon and P. Buneman, editors, Advances in Database Programing Languages, pages 347 377. ACM Press, 1990.

....of OO databases are proposed. Bancilhon [8] and Atkinson et al. in the ObjectOriented Database System Manifesto [6] list a number of features which they argue are essential for OO database systems. Parallel to this, a number of formalizations of OO models have been proposed, such as COL [1, 2, 3], F logic [33] HILOG [13] ILOG [29] IQL [4, 5] formalizations of 02 [36, 35] OBJ and related languages [20, 21, 22, 23, 25, 38] OBLOG [15, 19, 17, 43] and CMSL [50, 46] Beeri [9] gives a survey of some issues. Even though these papers are top down, there is not yet any root concept from ....

S. Abiteboul and S. Grumbach. COL: A logic-based language for complex objects. In J.W. Schmidt, S. Ceil, and M. Missikoff, editors, Advances in Database Technology - EDBT'88, pages 271 293. Springer, 1988. Lecture Notes in Computer Science 303.

....and the object oriented data model and query languages is the need for richer structure for the flexible modeling and querying of complex data. Although XML attempts to provide a framework for handling semistructured data, it encompasses most of the modeling features of complex object models [2, 4]. There are straightforward correspondences between the object oriented schemas and instances and XML DTDs and data. XOO7 was designed keeping in mind these similarities in data model of XML and object oriented approach. XOO7 is an adaptation of the OO7 Benchmark [13] Section 5 gives further ....

S. Abiteboul and S. Grumbach. COL: A Logic-Based Language for Complex Objects. EDBT, pages 271--293, 1988.

....fLiLy; Seang [123 St T oronto] John 30 fP hil; Pamg [456 Av Montreal] Lily 52 fg [321 St Calgary] Sean 57 fSam g [472 Av Regina] Relationlog is logic based language that supports logical variables as place holders. Variables in Relationlog must start with the underscore character. Unlike COL [4] in which variables are typed, same variables in Relationlog can range over atomic values, sets, tuples, lists and bags in different context. In order to support efficient access to deeply nested data, Relationlog supports powerful set and tuple terms. For example, if X; Y are variables, then h X; ....

....then h X; Y i is a set term which allows X and Y to range over the elements of the set which h X; Y i denotes. Similarly, X; Y ] is a tuple term which allows X and Y to range over the first and second elements of the tuple which [ X; Y ] denotes respectively. Languages such as LDL [27] and COL [4] do not support such kind of set terms so that it is cumbersome to access deeply nested data [23] Relationlog is a deductive database language that supports rules. Rules are used to define intensional relations from the extensional relations stored explicitly in the database. Figure 1 shows ....

S. Abiteboul and S. Grumbach. COL: A Logic-Based Language for Complex Objects. ACM TODS, 16(1):1--30, 1991.

....and the object oriented data model and query languages is the need for richer structure for the flexible modeling and querying of complex data. Although XML attempts to provide a framework for handling semistructured data, it encompasses most of the modeling features of complex object models [AG88, AS88] There are straightforward correspondences between the object oriented schemas and instances and XML DTDs and data. XOO7 was designed keeping in mind these similarities in data model of XML and objectoriented approach. XOO7 is an adaptation of the OO7 Benchmark [CDN93] Section 5 gives ....

S. Abiteboul and S. Grumbach. COL: A Logic-Based Language for Complex Objects. EDBT, pages 271--293, 1988.

....this paper with a summary of the main points and a discussion of future work. 2. Related Work There are several approaches to the integration of deductive and object oriented databases [12] They mostly fall into three categories, a) object oriented (OO) extensions to Datalog, like e.g. [1, 2], b) OO extensions to Prolog, like e.g. 28, 21, 19] and c) OO extensions to first order logic programming [18] The most notable disadvantage of approaches in categories a) and c) is that they represent theoretical departures from logic, therefore their usability and practicality in terms of ....

S. Abiteboul and S. Grumbach, COL: A logic-based language for complex objects, in J.W. Schmidt, S. Ceri and M. Missikoff, eds., Advances in Database Technology - EDBT'88, Int. Conf. on Extending Database Technology, LNCS 303, Springer-Verlag, pp. 271-293, 1988.

....26, 27] Moreover, there are theoretical foundations for studying such languages [4, 11] Functional languages have certain advantages over logical languages for complex objects. They have clear syntax (there is no need, for example, to give complicated syntactic rules for range restriction, cf. [1]) they can be typechecked, their semantics is generally easy to define and they allow a limited form of polymorphism. Since entries in databases are allowed to be or sets possibly containing other sets, the databases are no longer in the first normal form. Therefore, we have to deal with nested ....

S. Abiteboul and S. Grumbach, COL: a logic-based language for complex objects, In Advances in Database Programming Languages, ACM Press, 1990, pp. 271--293.

....Moreover, there are theoretical foundations for studying such languages [4, 12] Functional languages have certain advantages over logical languages for complex objects. They have clear syntax (there is no need, for example, to give complicated syntactic rules for range restriction like in COL [1]) they can be typechecked, their semantics is generally easy to define and they allow a limited form of polymorphism. Since entries in databases are allowed to be or sets possibly containing other sets, the databases are no longer in the first normal form. Therefore, we have to deal with nested ....

S. Abiteboul and S. Grumbach, COL: a logic-based language for complex objects, In Advances in Database Programming Languages, ACM Press, 1990, pages 271--293.

....program is a new program equivalent to the original one when applied to consistent databases and, in general, it contains more equated variables in its recursive rules. We show how the chase may be used for optimizing datalog programs. Then we use the chase to study the FD FD implication problem [1]. We prove that the problem is decidable for a class of linear datalog programs provided that the fds satisfy a minimality condition. Then, we prove that the FD FD implication problem can still be decided when we relax the linearity and minimality conditions on datalog programs of the previous ....

....of this work can be found in [5] 2 Related work Fds have been considered in the context of logic programming and databases by different authors. Mendelzon and Wood [9, 10] investigate how fds can be used to automate the insertion of the cut operator in Prolog like programs. Abiteboul and Hull [1] study how to take advantage of fds to add functions to datalog programs. They also present several decidability results relating to datalog programs that are evaluated on databases consistent with fds. Lambrichts et al. 7] also look into the problem of integrating functions in datalog and supply ....

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S. Abiteboul and S. Grumbach. COL: A logic-based language for complex objects. ACM TODS, 16(1):1--30, 1991.

....sets and also null unknown ( and inconsistent ( values. As a result, the null extended nested relational algebra operations as defined in [7] can be represented directly and more importantly recursively which makes it more powerful than other logic based languages. such as LPS [6] COL [1], LDL [4] and Relationlog [8] This work provides a firm logical foundation for nested relational and complex object databases that have both partial and complete tuples and sets. The rest of the paper is organized as follows. Section 2 presents the syntax of RLOG II . Section 3 defines the ....

.... 1 ; Child : X 2 ]i] Ancestor : h[Anc : X 1 ; Dec : X 4 ]i] P arent : h[P ar : X 1 ; Child : X 2 ]i] X 2 = X 3 ; Ancestor : h[Anc : X 3 ; Dec : X 4 ]i] The notion of stratification has been used in several logic based languages to give semantics to programs involving negation and or sets [1, 2, 4, 8]. We present a similar notion here. Let P be a program. We denote DP the set of all relation names in P . The relationships , and on DP are defined as follows: 1. R i R j if there is a rule in which R i is in the head, R j in the body, and R j is in a literal that is either negative or ....

S. Abiteboul and S. Grumbach. COL: A Logic-Based Language for Complex Objects. ACM TODS, 16(1):1--30, 1991.

....However, Telos assertion language is different from the FOL based languages usually offered in deductive databases, and the propositional 4 tuple foundations of Telos are fully novel. The functional constructs in our assertion language are reminiscent of similar constructs in the language COL [1] if the temporal arguments are omitted. Requirements modeling in Software Engineering is a third research area that has influenced the development of Telos. Following the pioneering work of [6] 14] and [25] a consensus seems to have emerged that a requirements model should include a ....

Abiteboul, S., and Grumbach, S. COL: a Logic-based Language for Complex Objects. In Proceedings of the International Conference on Extending Data Base Technology (Venice, Italy, March 1988).

....integrate the advantages of logic programming techniques and relational databases. Deductive databases extend the expressive power of the relational databases by means of rules for deduction and recursion. In recent years, deductive databases have been extended to subsume complex value databases [3, 6, 8, 13, 14, 17] and object databases [1, 4, 7, 12, 11, 15, 16] Rules in deductive databases are used to deduce information (new facts) from the data that is stored in the database. A rule is an expression of the form: A : L1, Ln where L1, Ln is the body of the rule and used for premises and A is ....

S. Abiteboul and S. Grumbach. COL: A LogicBased Language for Complex Objects. ACM TODS, 16(1):1-30, 1991.

....provides a simple and natural way to express queries on a relational database and is more expressive than the traditional relational languages. In the past several years, there have been some e orts to combine these two approaches, mainly by extending Datalog with set and tuple constructors [3, 7, 6, 9, 13, 14, 19]. Like Datalog, their natural use of xpoint construct allows to express transitive closure declaratively in polynomial space and time [4, 5] which makes them expressive enough while still practical for real database applications. However, most of the research on such kind of deductive databases ....

S. Abiteboul and S. Grumbach. COL: A Logic-Based Language for Complex Objects. ACM TODS, 16(1):1-30, 1991.

....ecient secondary storage access, etc. However, deductive databases based on relational databases only allow at relations and do not support data abstraction. As a result, more powerful deductive languages that support data with complex structures have been proposed, such as LDL [6] LPS [12] COL [1], Hilog [5] Relationlog [16] See [17] for an overview of some of these languages. Also, several deductive database systems that support data with complex structures have been developed, such as LDL [6] CORAL [23] and Relationlog [19] Object oriented concepts have evolved in three di erent ....

S. Abiteboul and S. Grumbach. COL: A Logic-Based Language for Complex Objects. ACM Trans. on Database Systems, 16(1):1-30, 1991.

....to a low level imperative program rather than a high level declarative program. y Recommended by Nicole Bidoit 1 2 Mengchi Liu On the other hand, powerful set representation mechanisms have been proposed in valueoriented deductive database languages such as LDL [13] CORAL [34] and COL [2]. In LDL, for example, sets can be used either in enumerated form or as a result of element grouping, set valued variables can be used to range over sets, and sets can contain sets. As a result, the above database task can be performed declaratively in LDL. Besides, in deductive object oriented ....

....allows both value oriented and object oriented features to be used together to take the advantages of both approaches. ROL directly supports the notion of schema and is a typed language without using typed symbols such as typed variables in programs and queries syntactically as in [29, 33] COL [2], Gulog [20] Instead, symbols of a ROL program are bound to certain types (called classes) based on the schema in the intended semantics of the program. Furthermore, ROL has a logical semantics that accounts in a clean and declarative fashion for ROL: A Deductive Object Base Language 3 all of ....

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S. Abiteboul and S. Grumbach. COL: A logic-based language for complex objects. ACM TODS, 16(1):1--30 (1991).

....both partial and complete information on sets, which combine LDL and F logic set treatments. Information about sets can be represented partially or completely. As a result, it is more expressive in terms of set representation than other deductive languages that support sets such as COL [3], LPS [25] LDL, revised O logic and F logic. Unlike most other deductive object database languages including O logic, revised O logic, C logic, IQL, IQL2, F logic, LOGRES, LLO [29] LOL [10] DLT [7] Gulog [18] and Rock Roll [9] the query language of ROL has a well defined, logic programming ....

....is a simple query which can be performed. The third task is complex but can be performed in ROL not only declaratively, but also object orientedly as discussed above. None of other deductive languages can do the same. In LDL, this task can be done declaratively but not object orientedly. In COL [3], CORAL [36] IQL [6] and Rock and Roll [9] the task cannot be done declaratively, but only imperatively by resorting to a low level imperative program. The last task can also be performed by using ROL updates. In addition, ROL supports the following tasks which are not supported in most ....

S. Abiteboul and S. Grumbach. COL: A logic-based language for complex objects. ACM TODS, 16(1):1--30, 1991. 28 LIU

....or completely. It has a uniform notion of schema for objects represented both extensionally and intensionally. Most importantly, ROL has a logical semantics that cleanly accounts for all of its object oriented and valueoriented features. A stratification in the spirit of several other researchers [2, 8, 12] is used. We follow the standard treatment of logic programming languages and show that for a stratified program, the unique minimal and supported model, when it exists, can be computed bottom up using a finite sequence of fixpoints and used as the intended semantics of the program. The rest of ....

....single valued or set valued determines o 0 as in the relational model, and it can be a value, an object identifier, a functor object or a complete set. As in the relational model, we do not allow o (the key) to be a partial set as it is incomplete. Here l corresponds to data function of COL [2] and method of IQL2 [1] and F logic [21] Arithmetic, set and comparison expressions in ROL are defined as in the standard arithmetic and settheoretic theories. ROL is a rule based language. We now introduce rules. A rule is of the form A : L 1 ; Ln , where the head A is a non negative ....

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S. Abiteboul and S. Grumbach. COL: A logic-based language for complex objects. ACM TODS, 16(1):1-- 30, 1991.

....database language [13, 41] However, Datalog is based on the traditional relational data model which imposes first normal form constraint and is found inadequate for many advanced database applications. In recent years, deductive databases have been extended to subsume complex object databases [4, 8, 14, 25, 28, 34] and object oriented databases [1, 5, 9, 10, 23, 22, 29, 31, 40] For simplicity, we only discuss deductive complex object databases in this section. Extension of the discussion to deductive object oriented databases is straightforward. In a deductive database, we can represent data either ....

S. Abiteboul and S. Grumbach. COL: A logic-based language for complex objects. ACM TODS, 16(1):1--30, 1991.

....0 is a sequence of atoms and the negation of atoms. As usual, rules are required to be safe or covered as de ned in [8, 35] A fact is a safe rule with empty body. The notion of strati cation has been used in several logical languages to give semantics to programs involving negation and or sets [1, 4, 8, 22, 24]. Normally, whether a program is strati ed can be statically determined by using a dependency graph based on the de ned symbols such as predicate, function or attribute symbols in the program. However in OLOG, we may have an atom which has no such symbol that we can use as a de ned symbol, such as ....

S. Abiteboul and S. Grumbach. COL: A Logic-Based Language for Complex Objects. ACM TODS, 16(1):1-30, 1991.

....the approaches that aim to formalize the notions, 19] does not address behavioral inheritance, and [19, 36, 66] and [80] do not address conflicts due to multiple inheritance or overriding. There are also a number of groups whose aim was to build object oriented databases or query languages. In [4], Abiteboul and Grumbach describe COL, a typed logic based language for manipulating complex objects. Besides base and derived relations, base and derived data functions are considered. Data functions can be functional or multi valued. In [6] Abiteboul and Kanellakis describe IQL, which is an ....

....[7] give a translation from a deductive object oriented language to Datalog with negation. Although this provides an evaluation procedure for deductive object oriented languages, it provides little insight into the semantics of such languages. Of the approaches where the aim is to build a system, [4] does not address inheritance, 4] and [6] do not address overriding, and [1, 4, 6] and [22] do not address multiple inheritance. 2.4 Summary In this chapter, we first describe concepts and current research in the area of deductive databases, and then we describe the key concepts of ....

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S. Abiteboul and S. Grumbach. COL: A logic-based language for complex objects. In F. Bancilhon and P. Buneman, editors, Advances in Database Programming Languages, pages 347--374. ACM Press/Addison-Wesley (Frontier Series), New York, 1990.

....mother ) none] isa person french isa person french orphan isa french; orphan Types have played an extremely important role in development and study of programming languages and database systems. In logic programming languages, the benefits of introducing types have been increasingly recognized [2, 21]. However, the circular reference in their data structures prevents them from having a type system similar to that of traditional programming languages. ROL provides a solution to that. A functor object in ROL is allowed to be associated with exactly one functor object class. For example, if the ....

S. Abiteboul and S. Grumbach. COL: A logicbased language for complex objects. ACM TODS, 16(1):1--30, 1991.

....Let sam[enroll(ai) be a query. Then the termination of the query evaluation cannot be guaranteed. Therefore, we impose the stratification restriction on a schema. The notion of stratification has been used to deal with negation and sets in several deductive languages such as Prolog [4] COL [1], LDL [7] and ROL [17] We present a similar notion here. Let K = C; isa; oe; be a schema and M denote the set of the update method names in method rules in . We define an ordering on M as follows. For two update method names m 1 2 M and m 2 2 M , m 1 m 2 if there is a method rule c[R] 2 ....

S. Abiteboul and S. Grumbach. COL: A logic-based language for complex objects. ACM TODS, 16(1):1--30, 1991.

....and complex object models (e.g. 1] Finally, some of these concepts will turn out to be essential to integrate new features in the following sections. Methods will be used to obtain extensibility and oid s are central for updates. 3 A RULE BASED LANGUAGE The language is built around the COL [2, 4] and IQL [5] languages. An implementation of COL is described in [9] In this section, we are concerned with a core language roughly that of [2] Fancier features are considered in the next sections. In particular, we assume here that methods are not overloaded (they are simply functions) and the ....

....Methods will be used to obtain extensibility and oid s are central for updates. 3 A RULE BASED LANGUAGE The language is built around the COL [2, 4] and IQL [5] languages. An implementation of COL is described in [9] In this section, we are concerned with a core language roughly that of [2]. Fancier features are considered in the next sections. In particular, we assume here that methods are not overloaded (they are simply functions) and the control is provided exclusively by a fixpoint. Two particular predicates belong to the language: equality ( and ownership (3) We also use ....

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S. Abiteboul and S. Grumbach. COL: a Logic-based Language for Complex Objects. In Proc. EDBT, 271--293, 1988.

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Serge Abiteboul and Stephane Grumbach. COL: a logic-based language for complex objects. In Francois Bancilhon and Peter Buneman, editors, Advances in Database Programming Languages, pages 347-374. ACM Press, New York, 1990. 10

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S. Abiteboul and S. Grumbach: "COL: a Logic-based Language for Complex Objects", Proc. EDBT 1988, Venezia, March 1988

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