E. Bertino. A view mechanism for object-oriented databases. In A. Pirotte, C. Delobel, and G. Gottlob, editors, Proc. of the 3rd Int. Conf. on Extending Database Technology, EDBT'92, LNCS 779, pages 136--151, Vienna, Austria, 1992. Springer-Verlag.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....instance, AB91] introduces virtual classes that show instances of base classes, thus allowing object preserving views (like the majority of OO view approaches) Additionally, imaginary classes are allowed and are populated by tuples defined by query results for which new object ids are computed. Ber92] suggest to allow object generating views motivated by the goal to support schema evolution via a view mechanism, which also requires the computation of object identifiers. As object generation is a useful feature, e.g. views defined via join operation require object generation and the RDF data ....

Elisa Bertino. A View Mechanism for Object-Oriented Databases. In Advances in DB-Technology, Proc. Intl. Conf. on Extending Database Technology (EDBT), number 580 in Lecture Notes in Computer Science, pages 136--151, Vienna, Austria, March 1992. Springer.

....(computed upon access) and has its place in an inheritance hierarchy. The main purposes of object oriented views are: providing a logical data independence data hiding and security simplification of a database schema and shorthand for queries data integration [5, 10] simulation of schema changes [4, 11, 14]. Although many approaches to object oriented views were proposed in scientific publications [e.g. 1, 2, 3, 4, 5, 6, 7, 10, 11, 14, 15, 17, 18, 19, 20, 21] existing commercial object oriented database systems (Uni SQL and 02) support views to a limited extent. For a few recent years a special ....

....view definition A concept of object oriented views is based on the object oriented paradigm with the notion of objects, classes, and inheritance. There are two basic approaches to view definition. In the first one a view is defined as a virtual class derived from one [3] or more classes [1, 2, 4, 5, 6, 10, 11, 14, 15, 18, 20, 21], called base classes. The second one defines a view as a portion of a database schema containing virtual as well as base classes [17] This concept was implemented in a MultiView system. In this system a view, called view schema, is constructed in the three following steps: first, virtual classes ....

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E.Bertino, A View Mechanism for Object-Oriented Databases, Advances in Database Technology (EDBT), 1992

....Complete covering means that the grouping provides a complete covering of the member class. For example, if TennisPlayer is a subclass of Employee, then in TennisPlayer##TennisClub the grouping class TennisClub covers all instances of the member class TennisPlayer. 2.7. 3 Viewpoints Viewpoint [Ber92, FKN 92, MPM96] is a binary relationship of pattern Class #View relating a class and a particular view on it according to a specific perspective. The viewpoint mechanism appears in various fields of information science under several terms [Myl98] In software development, it appears under ....

....a specific perspective. The viewpoint mechanism appears in various fields of information science under several terms [Myl98] In software development, it appears under the guises of workspaces, versions, and configurations [Kat90] for the support of cooperative work. In the database field [AB91, Ber92] the view mechanism is used to present partial data to di#erent user groups. In hypertext bases [PT93] and more general information bases [MPM96, MMP95] the notions of perspectives and contexts have been used to decom pose an information base in di#erent sub bases. In requirement engineering ....

E. Bertino. A view mechanism for object-oriented databases. In A. Pirotte, C. Delobel, and G. Gottlob, editors, Proc. of the 3rd Int. Conf. on Extending Database Technology, EDBT'92, LNCS 779, pages 136--151, Vienna, Austria, 1992. Springer-Verlag.

....of view classes forming aggregation hierarchy. 1. 3 Related Work Several approaches to object oriented views were proposed in scientific publications (the review can be found in [20] In the majority of approaches a view is defined as a virtual class derived from one or more classes [1] 3] [4], 5] 9] 10] 14] 17] 18] 19] called base classes. The approaches of MultiView [16] and eXor C [6] 7] consider a view as a more complex structure, i.e. a schema. In MultiView a view is deftned as a portion of a database schema containing virtual as well as base classes. In eXoT C a ....

Bertino, E.: A View Mechanism for Object-Oriented Databases. In proc. of Advances in Database Technology (EDBT'92), 3rd Intemational Conference on Extending Database Technology Preceedings

.... (by means of a declarative language like SQL) In addition, its functionalities should be extended to take into account the richness of the object oriented model (e.g. adding or redefining methods) In order to include such functionalities in OODBs, in the 90 s, numerous proposals were developed [1, 2, 8, 13, 16, 18] so that the three level ANSI SPARC architecture can be applied for OODBs as in RDBs. In general, these works use particular object models and they differ respect to the schema where the integration of derived classes is In the object oriented context, some authors identify the term view with ....

....is based on [15] and is characterised by the use of a repository that includes the conceptual schema, as well as the defined derived classes and external schemas. Derived classes are defined in the repository, where they are related with their base classes by means of the derivation relationship [2]. The use of derivation relationships in the repository to integrate derived classes makes easy the positioning problem. However, the derivation relationship is not used out of the repository. Therefore, external schemas do not include this relationship, because it would be an extension of the ....

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E. Bertino, "A View Mechanism for Object-Oriented Databases", Proc. of the 3rdEDBT, LNCS, Springer. 1992, pp. 136-151.

....with identifiers but the identifiers are temporarily generated and therefore are not persistent. The latter is object preserving: The objects contained in the result of a query are the instances of the base classes. Thus, object views are actually the instances of the base classes. As expressed in [6], providing persistent identifiers for object views is crucial if views are allowed to be defined additional attributes. However, the method proposed in [6] faces view update problem. In addition, update propagation has not been considered either. The role models[14] 3] allow objects to be ....

....result of a query are the instances of the base classes. Thus, object views are actually the instances of the base classes. As expressed in [6] providing persistent identifiers for object views is crucial if views are allowed to be defined additional attributes. However, the method proposed in [6] faces view update problem. In addition, update propagation has not been considered either. The role models[14] 3] allow objects to be extended with additional attributes and methods by adding roles. But time varying roles cannot be represented. The dynamic constraints and object migration[8] 19] ....

E.Bertino, A View Mechanism for ObjectOriented Databases, 3rd International Conference on Extending Database Technology, LNCS 580, pp.136-151 (1992)

....a standard, actually is the industry standard for persistent object storage. allows the definition of named queries, as a mechanism similar to relational views for defining derived classes. However, the definition of named queries does not take full advantage of the richness of the object model (Bertino, 1992; Kim et al. 1995) Then, in this paper, a system and a language for defining external schemas in ODMG OODBs are proposed. Both are based on (Samos, 1995) Some issues for extending the ODMG named queries are also proposed, in order to take advantage of the richness of the object data models. ....

....classes. Then, there is a contradiction, and different authors solve this problem generating intermediate classes in order to integrate the derived class (Rundensteiner, 1992a) or defining new relationships between the derived class and their base classes, such as the derivation relationship (Bertino, 1992), or the may be relationship (Santos, 1995) In addition, different semantics (object preserving or object generating) can be used in the derived class definition. In object preserving semantic, instances of the derived class are objects of the base classes. In object generating semantic, ....

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: Bertino, E. A View Mechanism for Object-Oriented Databases. In Proc. of the Third International Conf. on EDBT. pp. 136-151. 1992

....model, object views are mainly used to treat different aspects of change management. In the object model, changes can be applied to class structures and methods. Consequently, existing data may be affected and, controlling the impact of changes to persistent objects becomes an important issue [Ber91, FMZ94, FFM 95] The concept of view, dealing with change management issues, has been introduced by a number of authors working on the object model [AB91, Ber91, LST91] Moreover, to promote logical independence, data seen through a view should be manipulated as ordinary data. In ....

.... Consequently, existing data may be affected and, controlling the impact of changes to persistent objects becomes an important issue [Ber91, FMZ94, FFM 95] The concept of view, dealing with change management issues, has been introduced by a number of authors working on the object model [AB91, Ber91, LST91] Moreover, to promote logical independence, data seen through a view should be manipulated as ordinary data. In particular, updates must be allowed on such data. View updates have been extensively studied in the relational framework and should be revisited in the object context. First ....

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E. Bertino. A View Mechanism for Object-Oriented Databases. In Intl. Conference on Extending Data Base Technology, pages 136--151, Vienna, March 1991.

....we are developing an external schema definition mechanism based on its object model. This means the extension of the ODMG architecture according to the three levels ANSI SPARC architecture. This mechanism [Torr01a] based on [Samo95] is characterized by the use of the derivation relationship [Bert92] into the repository to integrate the derived classes. The use of the derivation relationship in the repository is not an extension of the object oriented paradigm, because it is not used in end user schemas (conceptual and external schemas) and the repository schema (metaschema) is still an ....

Bertino, E. 'A View Mechanism for Object-Oriented Databases'. In Proc. of the 3rd International Conference on Extending Database Technology. pp. 136-151. 1992

....image of the relational schema. We do not address this issue here but provide a simple language that can be used to implement these approaches and that supports efficient optimization strategies. This language is defined in the same spirit as existing object views languages (e.g. AB91, SLT91, Ber91, Run92, DdST95] Classes USER SYSTEM Optimized Algebraic Representation Preliminary Processing Optimization Code Generation Object DDL Program 1 2 3 5 4 6 Migration Control Environment Transaction Launching 7 P1 P2 . Pn Physical Constraints Specification ....

E. Bertino. A View Mechanism for Object-Oriented Databases. In Proc. of Intl. Conf. on Extending Data Base Technology, pages 136--151, Vienna, March 1991.

....remain very limited in terms of flexibility and recovery. There are two aspects to bulk loading : i) specifying source target transformations and (ii) populating the underlying database. The first aspect has been studied in different database research areas such as views [AB91, SLT91, Ber91, Run92, DdST95] format conversion and data integration [CHS 95, Kos96, DK97, TRV96, Jun, PGMW95, FFK 98, CDSS98, MZ98] The aim of these works were not always to achieve bulk loading and we cite them only to point out that if bulk loading aspects arise, our approach can be used in ....

E. Bertino. A View Mechanism for Object-Oriented Databases. In Proc. of Intl. Conf. on Extending Data Base Technology, pages 136--151, Vienna, March 1991.

....systems having different and diverse needs. The spectrum of the dynamic behavioral requirements is much wider and richer than merely the variation in the object structures (which nevertheless may be complex too) Recently, several approaches to integrate views in OODBMS have been reported (e.g. [1,4,7,9]) However, none of these addresses all the features outlined above. We propose a concept for the separation and integration of external and conceptual schema information in OODBMS which serves all of the above mentioned purposes. In this paper, we put the focus on the type lattices of the ....

E. Bertino: "A View Mechanism for Object-Oriented Databases." In: A. Pirotte, C. Delobel, G. Gottlob (eds.): Advances in Database Technology, - EDBT'92, Springer Verlag, 1992, pages 136-151.

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Bertino, E. #1992#. A View Mechanism for Object-Oriented Databases. In M. L. Brodie and S. Ceri, editors, Proc. Third Int'l Conf. on Extending Database Technology, pages 136# 151.

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E. Bertino. A view mechanism for object-oriented databases. In A. Pirotte, C. Delobel, and G. Gottlob, editors, Proc. of the 3rd Int. Conf. on Extending Database Technology, EDBT'92, LNCS 779, pages 136--151, Vienna, Austria, 1992. Springer-Verlag.

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E. Bertino, "A View Mechanism for Object-Oriented Databases," Proc. Int'l Conf. Extending Data Base Technology, Vienna, Austria, Springer Lecture Notes in Computer Science, vol. 580 , 1992.

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E. Bertino. A view mechanism for object-oriented databases. In Proc. Intl. Conf. on Extending Database Technology (EDBT), volume 580 of LNCS, pages 136-151. Springer-Verlag, 1992.

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Elisa Bertino. A View Mechanism for Object-Oriented Databases. In Advances in DB-Technology, Proc. Intl. Conf. on Extending Database Technology (EDBT), number 580 in Lecture Notes in Computer Science, pages 136--151, Vienna, Austria, March 1992. Springer.

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Elisa Bertino. A View Mechanism for Object-Oriented Databases. In 3rd International Conference on Extending Database Technology, March 23 - 27, 1992, Vienna, Austria. Springer-Verlag LNCS, 1992.

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E. Bertino. A View Mechanism for Object-Oriented Databases. In Proc. of Intl. Conf. on Extending Database Technology (EDBT), pages 136--151, March 1992.

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Bertino E. A view mechanism for object-oriented databases. In Proc. Int. Conf. on Extending Database Technology (EDBT), Vienna, 1992. Springer-Verlag.

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E. Bertino. A view mechanism for object-oriented databases. In A. Pirotte, C. Delobel, and G. Gottlob, editors, Proc. of the 3rd Int. Conf. on Extending Database Technology, EDBT'92, LNCS 779, pages 136--151, Vienna, Austria, 1992. Springer-Verlag.

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E. Bertino, "A view mechanism for object-oriented databases," In Proc. Int. Conf. Extending Data Base Technol. (Viena, Austria, March 1991), pp. 136--151.

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Elisa Bertino. A view mechanism for object-oriented databases. In International Conference on Extending Database Technology, pages 136--151, Vienna, Austria, 1992. 145

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: E. Bertino, A View Mechanism for Object-Oriented Databases , Advances in DBTechnology, Proc. Intl. Conf. on Extending Database Technology (EDBT), Lecture Notes in Computer Science, Number 580, pp. 136-151, Springer, March 1992.

No context found.

Bertino E. A view mechanism for object-oriented databases. Proceedings of the 3rd International Conference on Extending Database Technology (EDBT'92), 1992; 136--151.

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