C. Souza dos Santos. Design and Implementation of Object--Oriented Views. In N. Revell and A.Min. Tjoa, editors, Proc. of the 6th International Conference on Database and Expert Systems Applications, number 978 in LNCS, London, England, September 1995. Springer Verlag.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....back and forth between the root database and the view. Our conviction that the primitives of value import and code import are necessary and sufficient is supported by extensive programming experience with one of the few industrial strength OO view systems currently available, namely O 2 Views [SdS95]. 1 From the outset, our view specification mechanism is independent of any particular programming model. Yet, in order to be able to concretely assess the ramifications of our mechanism, we have implemented it on top of the formalism of method schemas. Method schemas ( AKW90, AKRW95] see also ....

C. Souza dos Santos. Design and implementation of object-oriented views. In N. Revell and A. Min Tjoa, editors, Database and Expert Systems Applications, Lecture Notes in Computer Science, pages 91-- 102. Springer, 1995.

....implemented with the O 2 C programming language on top of the O 2 system. This manual focuses on the use of the O 2 Views prototype and do not go into detail on the view mechanism and its motivations, nor on the implementation of the prototype itself. For more details, the reader is referred to [AB91, SDA94, dS94]. In addition, the reader is supposed to know the O 2 data model as well as the O 2 system [Tec94] Knowledge of another OODBMS must be sufficient to follow the manual but in order to be able to use the prototype some basic knowledge of the O 2 system is required. The software presented in this ....

Cassio Souza dos Santos. Design and Implementation of an Object-Oriented View Mechanism. In 10`emes Journ'ees Bases de Donn'ees Avanc'ees, Clemont-Ferrand, September 1994, Rocquencourt - France, 1994.

....the physical objects for an application and propagates all accesses to the original local objects. The concept of surrogate is strictly equilavent to the concept of core attribute introduced by Abiteboul and Bonner [Abiteboul91] this concept has also been chosen in the O2view implementation [Souza94] 3.2 Integrated Schema Definition Four different kinds of classes are identified in IRO DB as described in Figure 5 [Fankhauser94] i) external classes, ii) imported classes, iii) derived classes and (iv) standard classes. External Classes correspond to the existing classes made ....

Souza dos Santos C, "Design and Implementation of an Object-Oriented View Mechanism", International Conference on Extended DataBase Technology, p213-232, Cambridge, March 1994.

....but there is common ground between them. In [3] the Ansi X3 Sparc group distinguished between three levels of data representations when designing a database: the conceptual level which denes the database schema by using the DBMS data model, the external level which denes sub schemas or views [20, 21] on top of the schema database and the physical level which implements data and takes into account constraints in relation with the machine. The schema dened at the conceptual level contains the totality of information of the real world. Its elaboration, especially in the case of large ....

C. Souza Dos Santos. Design and implementation of object-oriented views. In 6th International Conference on Database and EXpert systems Applications, DEXA95, volume 978 of Lecture Notes in Computer Science, pages 91102, 1995.

.... Views and Database Restructuring (extended abstract) Zo e Lacroix and Claude Delobel y and Philippe Br eche z Abstract We present a formal data model for views in Object DataBase Systems (ODBS) which is a continuation of the work presented in [AK89, AB91, dSDA94, dS95a] The main contribution of this paper is the formalization of views as a transformation mechanism for databases using a generalization of referent proposed in [dS95b] We define an IQL like language adapted to manipulate referents. The view based transformation is achieved in two steps: an ....

....the relational context, commercial databases only provide view mechanisms that are restrictive whereas none of the commercial object databases provides user with any such mechanism. To the best of our knowledge, only two prototypes exist in this domain, namely, MultiView TSE [KR96] and O 2 Views[dS95a, dS95b] Very little has been said about a formal model for object views. The main contribution of this paper is to propose a formal model inspired by the work presented in [dS95b] in line with IQL [AK89] and based on the data model in [AHV95] 1 and O 2 [BDK92, LRV88] This is a continuation ....

[Article contains additional citation context not shown here]

C. Souza dos Santos. Design and Implementation of Object--Oriented Views. In N. Revell and A.Min. Tjoa, editors, Proc. of the 6th International Conference on Database and Expert Systems Applications, number 978 in LNCS, London, England, September 1995. Springer Verlag.

....Cedex. Projet Verso I.N.R.I.A. Rocquencourt. Domaine de Voluceau. BP. 105. 78 153. Le Chesnay Cedex France ABSTRACT. We present a formal data model for views in Object DataBase Systems (ODBS) which is a continuation and a formalization of the work presented before in [AK89, AB91, ADdS94, dS95a] The main contribution of this paper is the formalization of the views as a transformation mechanism for databases using a generalization of the referent proposed in [dS95b] The transformation is achieved in two steps: an extension of the source base followed by a projection of the extended ....

....challenges involved supporting our view mechanism and points to new perspectives. R ESUM E. Nous pr esentons un mod ele de donn ees formel pour les vues des Syst emes de Bases de Donn ees Objet (SBDO) qui est une extension et une formalisation des travaux pr esent es dans [AK89, AB91, ADdS94, dS95a] La principale contribution de cet article est la formalisation des vues comme m ecanisme de transformation de bases en utilisant une g en eralisation du r ef erent propos e dans [dS95b] Cette transformation de vue est effectu ee en deux etapes, extension de la base source suivie d une ....

[Article contains additional citation context not shown here]

C. Souza dos Santos. Design and Implementation of Object--Oriented Views. In N. Revell and A.Min. Tjoa, editors, Proc. of the 6th Interna- tional Conference on Database and Expert Systems Applications, number 978 in LNCS, London, England, September 1995. Springer Verlag.

....BP. 105, 78 153 Le Chesnay Cedex, France only provide view mechanisms that are restrictive whereas none of the commercial object databases provides user with any such mechanism. To the best of our knowledge, only two prototypes exist in this domain, namely, MultiView TSE [KR96] and O 2 Views [dS95a,dS95b] Very little has been said about a formal model for object views. The main contribution of this paper is to propose a formal model inspired by the work presented in [dS95a,dS95b] in line with IQL [AK89] and based on the data model in [AHV95] and O 2 [BDK92,LRV88] We further extend these ....

....To the best of our knowledge, only two prototypes exist in this domain, namely, MultiView TSE [KR96] and O 2 Views [dS95a,dS95b] Very little has been said about a formal model for object views. The main contribution of this paper is to propose a formal model inspired by the work presented in [dS95a,dS95b] in line with IQL [AK89] and based on the data model in [AHV95] and O 2 [BDK92,LRV88] We further extend these proposals with the construction of complex referents, that can express multi instantiation and, consequently new definitions for schema and base. It seems first natural to ....

[Article contains additional citation context not shown here]

C. Souza dos Santos. Design and Implementation of Object--Oriented Views. In N. Revell and A.Min. Tjoa, editors, Proc. of the 6th International Conference on Database and Expert Systems Applications, number 978 in LNCS, London, England, September 1995. Springer Verlag.

.... 33 (1) 39 63 56 79 fax: 33 (1) 39 63 56 74 lacroix saul.cis.upenn.edu, Claude.Delobel inria.fr , Philippe.Breche inria.fr Abstract We present a formal data model for views in Object DataBase Systems (ODBS) which is a continuation and a formalization of the work presented in [AK89, AB91, ADdS94, dS95a] The main contribution of this paper is the formalization of the views as a transformation mechanism for databases using a generalization of referent proposed in [dS95b] The view based transformation is achieved in two steps: an extension of the source base followed by a projection of the ....

....object database systems, views, data model, object algebra, multiple instantiation, database transformation. Nous pr esentons un mod ele de donn ees formel pour les vues des Syst emes de Bases de Donn ees Objet qui est une extension et une formalisation des travaux pr esent es dans [AB91, ADdS94, dS95a] La principale contribution de cet article est la formalisation des vues comme m ecanisme de transformation de bases en utilisant une g en eralisation du r ef erent propos e dans [dS95b] Cette transformation de vue est effectu ee en deux etapes: une extension de la base source suivie d une ....

[Article contains additional citation context not shown here]

C. Souza dos Santos. Design and Implementation of Object--Oriented Views. In N. Revell and A.Min. Tjoa, editors, Proc. of the 6th International Conference on Database and Expert Systems Applications, number 978 in LNCS, London, England, September 1995. Springer Verlag.

....could, for example, add a set valued attribute to each object which contains references to other objects which actually stand for other roles of the real world entity. Or we could have objects denoting a role pointing to a root object, which is similar to what has been proposed for views in O 2 [dS95] Another approach is to add a key value to objects. This key value is unique for one real world entity. Objects in the database system with the same key value refer to the same real world entity. The first and second approaches lead to quite a lot of pointer chasing and it is hard to keep the ....

C. S. dos Santos. Design and Implementation of Object-Oriented Views. In Proceedings of the Database and Expert Systems Applications (DEXA) Conference, pages 91--102, 1995.

....simple properties of our framework. 1 Introduction Schema modification is an important means for adapting an information system in an evolving environment to changing requirements. Its study has impact on many database research areas as for example views in object databases [AB91, MP96, SLT91, Sou95, Wie91] schema evolution [Zic92] and (on object level) database versions [CJ90] An information system has several components, which can be subject to change. Figure 1 shows a layered approach as suggested e.g. in [EGH 92] to model these components. The data type component describes the ....

C. Souza dos Santos. Design and implementation of object-oriented views. Lecture Notes in Computer Science, 978, 1995.

....leads to the general observation, that version management with lazy object duplication can never be implemented on top of a database system, that does not support version management. 2. 3 Views The O 2 Views model, implementation and philosophy are described in a number of recent publications [dS95, SAD94, AB91] In [AdS95] we propose a related model where the concepts of views, versions and roles are treated in a uniform way. Software engineering environments built on top of an object database system store a great amount of information concerning a system development project, such as user ....

....observation, that version management with lazy object duplication can never be implemented on top of a database system, that does not support version management. 2. 3 Views The O 2 Views model, implementation and philosophy are described in a number of recent publications [dS95, SAD94, AB91] In [AdS95] we propose a related model where the concepts of views, versions and roles are treated in a uniform way. Software engineering environments built on top of an object database system store a great amount of information concerning a system development project, such as user requirements, system ....

C. Souza dos Santos. Design and Implementation of an Object-Oriented View Mechanism. In Proc. of the 5 th Int. Conference on Database and Expert System Applications, London, UK, Lecture Notes in Computer Science, pages 91--102. Springer, 1995.

....Cedex. Projet Verso I.N.R.I.A. Rocquencourt. Domaine de Voluceau. BP. 105. 78 153. Le Chesnay Cedex, France ABSTRACT. We present a formal data model for views in Object DataBase Systems (ODBS) which is a continuation and a formalization of the work presented before in [AK89, AB91, ADdS94, dS95a] The main contribution of this paper is the formalization of the views as a transformation mechanism for databases using a generalization of the referent proposed in [dS95b] The transformation is achieved in two steps: an extension of the source base followed by a projection of the extended ....

....challenges involved supporting our view mechanism and points to new perspectives. R ESUM E. Nous pr esentons un mod ele de donn ees formel pour les vues des Syst emes de Bases de Donn ees Objet (SBDO) qui est une extension et une formalisation des travaux pr esent es dans [AK89, AB91, ADdS94, dS95a] La principale contribution de cet article est la formalisation des vues comme m ecanisme de transformation de bases en utilisant une g en eralisation du r ef erent propos e dans [dS95b] Cette transformation de vue est effectu ee en deux etapes, extension de la base source suivie d une ....

[Article contains additional citation context not shown here]

C. Souza dos Santos. Design and Implementation of Object--Oriented Views. In N. Revell and A.Min. Tjoa, editors, Proceedings of the 6th International Conference on Database and Expert Systems Applications, number 978 in LNCS, London, England, September, 1995. Springer Verlag.

....ensure that the placement of a view does not violate the semantics of a well formed view inheritance hierarchy. Recently, two view models have been proposed which also solve the view placement problem by combining the view derivation and view inheritance relationships: the extension presented in [42, 41] to the view model described in [1] for the O 2 system, and the view mechanism for the UniSQL system [27] 3.3. Object generating vs object preserving views If views are to be used as classes, it is essential that their instances are objects, that is, that they are provided with persistent ....

Souza dos Santos, C. (1995). Design and Implementation of Object-Oriented Views. In N. Revell and A M. Tjoa, editors, Proc. Sixth International Conference and Workshop on Database and Expert Systems Applications, number 978 in Lecture Notes in Computer Science, pages 91--102.

....Some systems such as Pegasus [ADD 91] OPM [CKMS97] or a system supporting materialized views defined with ILOG [HY90,Cha94] include view definition capabilities over object based databases. To the best of our knowledge, the more advanced prototypes are MultiView TSE [KR96] and O 2 Views [dS95a,dS95b] But even these do not provide the flexibility and generality a user may expect from a view mechanism. Very little has been said about a formal model for object views. Most of the literature focuses on the semantic aspect of object views (how to populate virtual classes) but no formal ....

....to populate virtual classes) but no formal model that deals with syntax (how the virtual classes are inserted in the hierarchy) as well as semantics is proposed. Our view mechanism really structures the view. The main contribution of this paper is a formal model inspired by the work presented in [dS95a,dS95b] in line with IQL [AK89] and based on the data model in [AHV95] and O 2 [BDK92,LRV88] We further extend these proposals with the construction of complex referents that can express multi instantiation and, consequently new definitions for schema and instance. We propose a formal model for ....

[Article contains additional citation context not shown here]

C. Souza dos Santos. Design and Implementation of Object--Oriented Views. In N. Revell and A.Min. Tjoa, editors, Proc. of the 6th International Conference on Database and Expert Systems Applications, number 978 in LNCS, London, England, September 1995. Springer Verlag.

....Cassio Souza dos Santos Projet Verso. INRIA Rocquencourt. Domaine de Voluceau BP. 105. 78 153 Le Chesnay Cedex France ABSTRACT. We present a mechanism for updating views in Object DataBase Systems (ODBS) Starting from an existing view data model, chronologically in line with [AB91, ADdS94, dS95a] we extend it to provide data update ability. Updates to view data are performed in such a way that consistency with root data is preserved. The main contribution of this paper is to detail such a mechanism together with its corresponding data model. This is, to the best of our knowledge, the ....

....issues on implementation on top of the O2 ODBS and examine related work. R ESUM E. Nous pr esentons un m ecanisme de mise a jour de vues dans les Syst emes de Bases de Donn ees Objet (SBDOs) Partant d un mod ele de donn ees de vues existant, dans la lign ee des travaux [AB91, ADdS94, dS95a] nous etendons ce mod ele pour prendre en compte la mise a jour de donn ees de vues. Cette mise a jour est effectu ee en pr eservant la coh erence avec les donn ees sources. La principale contribution de cet article est de d etailler ce m ecanisme et son mod ele de donn ees attenant. A ....

[Article contains additional citation context not shown here]

C. Souza dos Santos. Design and Implementation of Object--Oriented Views. In N. Revell and A.Min. Tjoa, editors, Proc. of the 6th International Conference on Database and Expert Systems Applications, number 978 in LNCS, London, England, September 1995. Springer Verlag.

....France tel. 33) 1 39 63 52 75 fax: 33) 1 39 63 56 74 e mail: fSihem.Amer Yahia,Philippe.Breche,Cassio.Souzag inria.fr July 24, 1996 Abstract We present a mechanism for updating views in Object DataBase Systems (ODBS) Starting from an existing view data model, chronologically in line with [1, 2, 14], we extend it to provide data update ability. Updates to data views are performed in such a way that consistency with root data is preserved. The main contribution of this paper is to detail such a mechanism together with its corresponding data model. This is, to the best of our knowledge, the ....

....VDLs [8, 22, 23] differ slightly according to the underlying view data model and to the particular aspects addressed such as data integration and schema evolution. Our VDL is an extension of O 2 C, the native language of O 2 [15] It implements the view data model O 2 Views, as defined in [2, 14] and is based on the OQL query language[5] which is the object oriented SQL like query language of the ODMG 93 standard [5] 2.1 Extended O 2 data model In the following, we introduce the main features of the O 2 object oriented data model and we proceed with the definition of object referents ....

C. Souza dos Santos. Design and Implementation of Object--Oriented Views. In N. Revell and A.Min. Tjoa, editors, Proc. of the 6th International Conference on Database and Expert Systems Applications, number 978 in LNCS, London, England, September 1995. Springer Verlag.

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