M. Jeusfeld and M. Staudt, "Query optimization in deductive object bases", in Query Processing for Advanced Database Applications, (Freytag et al., eds.), Morgan-Kaufmann, 1993. 29  Home/Search   Document Details and Download   Summary   Related Articles   Check

....di Ingegneria, Universit a di Modena, Via G. Campi 213 A, I 41100 Modena, Italy. e mail: f dbeneventano, sbergamaschi, csartori g deis.unibo.it generalize it to deductive databases [17, 18, 19, 8] More recently, some efforts have been made to perform semantic query optimization in OODBs [9, 11, 16, 6, 1, 2]. The main point is that OODBs provide a very rich type (class) system able to directly represent a subclass of integrity constraints in the database schema. By exploiting schema information as, for instance, inheritance relations between types (classes) it is possible to perform semantic query ....

M. Jeusfeld and M. Staudt. Query optimization in deductive object bases. In Freytag, Maier, and Vossen, editors, Query Processing for Advanced Database System. Morgan Kaufmann Publishers, Inc., June 1993.

....low level rule implementation seem to be the main weaknesses, although a more careful evaluation remains to be done. 12 Related Systems A number of other deductive database systems have been developed in the past few years. These include (in alphabetical order) Aditi [VRK 91] ConceptBase [JS93] EKS V1 [VBKL90] Glue NAIL [MUVG86, PDR91] LDL [NT89, CGK 90] LDL [AO93] LOLA [FSS91] Starburst SQL [MPR90] and XSB [SSW93] There are many similarities between CORAL and these systems. However, there are several important differences, and CORAL extends the above systems in the ....

M. Jeusfeld and M. Staudt. Query optimization in deductive object bases. In J.C. Freytag, G. Vossen, and D. Maier, editors, Query Processing for Advanced Database Applications. Morgan-Kaufmann, 1993.

....of persistent relations using EXODUS illustrates the utility of such extensibility. 8 Related Systems There are many similarities between CORAL and deductive database systems such as Aditi [28] EKS V1 [29] LDL [13, 3] Glue NAIL [11, 15] Starburst SQL [12] DECLARE [9] ConceptBase [6] and LOLA [4] However, there are several important differences, and CORAL extends all the above systems in the following ways: 1. CORAL supports a larger class of programs, including programs with non ground facts, non stratified negation and set generation. 2. CORAL supports a wide range of ....

M. Jeusfeld and M. Staudt. Query optimization in deductive object bases. In G. J.C. Freytag, G. Vossen and D. Maier, editors, Query Processing for Advanced Database Applications. Morgan-Kaufmann, 1993.

....integrity constraints) and the necessary formalism (in term of satisfiability, provability and inference mechanism) for developing a theory of semantic query optimization. More recently, some efforts have been made to perform semantic query optimization in Object Oriented Database Systems (OODBs) [11, 14, 20, 8]. The main point is that OODBs provide a very rich type (class) system able to directly represent a subclass of integrity constraints in the database schema. By exploiting schema information as, for instance inheritance relations between types (classes) it is possible to perform semantic query ....

M. Jeusfeld and M. Staudt. Query optimization in deductive object bases. In Freytag, Maier, and Vossen, editors, Query Processing for Advanced Database System. Morgan Kaufmann Publishers, Inc., June 1993.

....enforce consistency of a database but also to optimize user queries. During the last decade, many efforts have been made to improve this technique and to generalize it to deductive databases [17, 18, 19, 8] More recently, some efforts have been made to perform semantic query optimization in OODBs [9, 11, 16, 6, 1, 2]. The main point is that OODBs provide a very rich type (class) system able to directly represent a subclass of integrity constraints in the database schema. By exploiting schema information This research has been partially funded by the LOGIDATA project of the National Research Council ....

M. Jeusfeld and M. Staudt. Query optimization in deductive object bases. In Freytag, Maier, and Vossen, editors, Query Processing for Advanced Database System. Morgan Kaufmann Publishers, Inc., June 1993.

....sort merge and hash join are used. An overview is provided in [VRK 91] 6 The ConceptBase system, developed since 1987 at the Universities of Passau and Aachen in Jarke s group, seeks to combine deductive rules with a semantic data model based on Telos. The language aspects are presented in [JS93] The system also provides support for integrity constraints; this is described in [JJ91] ConceptBase has been used in a number of applications at various universities in Europe, and is now being commercially developed. The CORAL project at U. Wisconsin, which was started in 1988, can also be ....

....have not verified the information presented below our summary is based upon information provided by the implementors. Name Developed Refs. Recursion Negation Aggregation Aditi U. Melbourne [VRK 91] General Stratified Stratified COL INRIA [AG91] Stratified Stratified Concept U. Aachen [JS93] General Locally No Base Stratified CORAL U. Wisconsin [RSS92b] General Modularly Modularly Stratified Stratified EKS VI ECRC [BLV93] General Stratified Superset of Stratified LogicBase Simon Fraser U. Linear, some Stratified No nonlinear DECLARE MAD Intelligent [KS93] General Locally Superset of ....

M. Jeusfeld and M. Staudt. Query optimization in deductive object bases. In G. Vossen J.C. Freytag and D. Maier, editors, Query Processing for Advanced Database Applications. Morgan-Kaufmann, 1993.

.... the last decade, many efforts have been made to improve this technique and to generalize it to deductive databases [ Shenoy and Ozsoyoglu, 1989; Siegel et al. 1992; Chakravarthy et al. 1990 ] More recently, some efforts have been made to perform semantic query optimization in OODBs [ Chan,1992; Jeusfeld and Staudt,1993; Pang et al. 1991; Buchheit et al. 1994; Beneventano et al. 1993; Bergamaschi and Nebel,1993 ] The main point is that OODBs provide a very rich type (class) system able to directly represent a subclass of integrity constraints in the database schema. By exploiting schema information as, for ....

M. Jeusfeld and M. Staudt. Query optimization in deductive object bases. In Freytag, Maier, and Vossen, editors, Query Processing for Advanced Database System. Morgan Kaufmann Publishers, Inc., June 1993.

....a non linear recursion. Thus the transformation from a DOOD program to a Datalog program may produce more complex recursions than the original ones in DOOD programs. 2 There are research prototypes which integrate object orientation with deductive database languages, e.g. COMPLEX [2] ConceptBase [8] and Coral [11] However, these systems typically extend deductive database languages such as Datalog with limited object oriented features [2, 8] or a C type system [11] Programs are first translated into Horn clause like programs such as Datalog, and then evaluated with the existing ....

....in DOOD programs. 2 There are research prototypes which integrate object orientation with deductive database languages, e.g. COMPLEX [2] ConceptBase [8] and Coral [11] However, these systems typically extend deductive database languages such as Datalog with limited object oriented features [2, 8] or a C type system [11] Programs are first translated into Horn clause like programs such as Datalog, and then evaluated with the existing deductive query evaluation methods. Although object orientation is not explicitly supported, XSB [10] provides a platform for implementing ....

M. Jeusfeld and M. Staudt. Query optimization in deductive object bases. In J. C. Freytag, D. Maier, and G. Vossen, editors, Query Processing for Advanced Database Systems, pp. 146--176. Morgan Kaufmann, 1994.

....WDPH(p;w) Gamma A:#suff(p; d) A:#ag(w; d) 24 where the new specialized forms A:#tak, A:#suff , and A.#ag of the literal A allow a more efficient access directly to the instances of the concerned attribute classes. This technique can be extended to views containing complex objects as well [27]. The rule view of queries allows the application of the standard deductive optimization techniques. One example is the application of the magic set rewriting method [8] to the rules generated from query classes. A bottom up fixpoint procedure using the rewritten rules only computes information ....

M. Jeusfeld and M. Staudt, "Query optimization in deductive object bases", in Query Processing for Advanced Database Applications, (Freytag et al., eds.), Morgan-Kaufmann, 1993. 29

....and the procedure is run on this input. The system modifies the query evaluation plans by adding access operations to the stored extensions of subsuming views, thus restricting the search space. We plan to implement such a subsumption checker within the deductive object base manager ConceptBase [JS93, SNJ93] which offers a schema and query language very similar to DL. 4 A Calculus for Deciding Subsumption The basic idea for deciding subsumption between a query concept C and a view concept D is as follows. We take an object o and transform C into a prototypical interpretation where o is an ....

....The first user asking this query triggers the normal evaluation. A control component ( trader ) memorizes the query and the location of the answer (the view) A new query is then checked for subsumption against such views. Such an environment is currently set up in a quality management project [JJS93] where autonomous data intensive tools cover certain aspects of quality management in the industrial product life cycle. Since the trader manipulates schema and query descriptions it provides an excellent test bed for the application of the techniques presented in this paper. There are a couple ....

M. Jeusfeld and Martin Staudt. Query optimization in deductive object bases. In Freytag, Maier, and Vossen, editors, Query Processing for Advanced Database Systems. Morgan Kaufmann, June 1993.

....any evaluation method from this area is applicable. Optimization of rules and integrity constraints benefits from the predefined axioms of the object model by elimination of redundant predicates [15] This also enhances the maintenance of materialized views, i.e. stored answers to a query [16]. Recently, compilation of deductive rules into algebra expressions has been added to ConceptBase. It profits from the fact that the object model provides an access predicate for each class attribute. 3.4 Queries as Concepts In programming languages objects (variables, functions, etc. usually ....

M.A. Jeusfeld and M. Staudt, "Query optimization in deductive object bases", in Query Processing for Advanced Database Applications, (Freytag et al., eds.), Morgan-Kaufmann, 1993.

....our algorithm is run as explained above. The system modifies the query evaluation plans by adding access operations to the stored extensions of subsuming views, thus restricting the search space. We plan to implement such a subsumption checker within the deductive object base manager ConceptBase [JS93, SNJ93] which offers a schema and query language very similar to DL. 5 Related Work Our work relates to several fields of research in databases and AI. We shortly discuss the relationship to optimization of conjunctive queries, to semantic query optimization, and query optimization in existing OODB ....

M. Jeusfeld and Martin Staudt. Query optimization in deductive object bases. In Freytag, Maier, and Vossen, editors, Query Processing for Advanced Database Systems. Morgan Kaufmann, June 1993.

....answer instances of AffectedProgram to programs with owner Bill resp. a subclass of Agent as owner. The semantics of query classes is given by a mapping to rules concluding special query literals. Like ordinary deduction rules and integrity constraints these rules can be transformed to Datalog : [JS91]. 3.3 Evaluation The concept of query classes for defining views and ad hoc querying yields a uniform representation of queries and other objects which is very flexible and expressive. Subsystems can exchange information via query classes by defining views that cover not only their private ....

Jeusfeld M., Staudt M., "Query optimization in deductive object bases", Technical Report 'Aachener Informatik-Berichte' Nr.91-26, RWTH Aachen, to appear in Query Processing for Advanced Database Applications, (Freytag et al., eds.), MorganKaufmann, 1993.

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