Barbedette, G.: Schema modifications in the LISPO2 persistent object-oriented language. In Proceedings of ECOOP'91 (P. America, ed.), LNCS 512, Geneva, Switzerland, July 1991, Springer-Verlag.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....and their code does not result in run time errors or unexpected results. The resolution of behavioral inconsistencies is what leads to method evolution. The schema evolution facilities in most of today s database systems are restricted to deal with structural inconsistencies exclusively [CPLZ91, Bar91, AH88, BKKK87, PS87, SZ86] some systems don t even propagate the changes to the persistent object store, and none of them provides a mechanism for resolving behavioral consistency. However, as it is clear from both types of inconsistencies, it is important to propagate the modifications of the ....

....constrained by the updated schema and the updated object base. Unlike structural inconsistency, none of today s database systems provides a mechanism to restore behavioral consistency. Some papers propose possible mechanisms, but none of them have been implemented [Opd92, Zic92, Gri91, Wal91, Bar91] a detailed discussion of these will be given later in section 3.1) There are primarily two reasons why changes to methods have only recently begun to be considered by the research community. The first is that for database systems, the key focus of the systems are the data, and the update of ....

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Gilles Barbedette. Schema modifications in the LISPO 2 persistent object-oriented language. In Pierre America, editor, European Conference on Object-Oriented Programming, pages 77--96, Geneva, Switzerland, July 1991. Springer Verlag, Lecture Notes in Computer Science. Vol. 512.

....components in a long running application such as a server. The upgrade must not require the application to shut down and restart. On the Java platform, this ability translates to reloading a subset of the classes already loaded in a running virtual machine. It corresponds to the schema evolution [3] problem, which could be rather difficult to solve in general. Here are some of the difficulties: ffl There may be live objects that are instances of a class we want to reload. These objects must be migrated to conform to the schema of the new class. For example, if the new version of the class ....

Gilles Barbedette. Schema modifications in the LISP O2 persistent object-oriented language. In European Conference on Object-Oriented Programming, pages 77--96, July 1991.

....Most existing approaches support a Schema evolution approach, in which existing specifications may be changed, but existing instances and applications must be made to comply with the new definition. Existing instances may be physically converted, either eagerly (GemStone [3] or lazily (LISPO 2 [4] 1 ) or they may be made to emulate the new specification (ORION [5] in such a way that they behave as if they were instances of the new specifications. This approach is problematic as existing applications and instances must be modified to correspond with the new specification. This may not ....

Gilles Barbedette. Schema Modifications in the LISPO 2 Persistent Object-Oriented Language. In ECOOP '91. European Conference on Object-Oriented Programming, Geneva, Switzerland, pages 77--96. Springer-Verlag, 1991.

....SMM work is solely concerned about how objects may behave in accordance with other versions of its creation class, by (transitive) application of coercion functions. For the evolution approach only the most recent class version is interesting. Most frequently (e.g. ORION [2] GemStone [1] and O 2 [11]) a restricted taxonomy of change is assumed along with predefined rules for how the object base is to be affected by the particular change. OTGen [12] allows for the specification of schema level modifications as well, but still upgrades the database to make all objects comply with the most ....

Gilles Barbedette. Schema Modifications in the LISPO 2 Persistent ObjectOriented Language. In ECOOP '91. European Conference on Object-Oriented Programming, Geneva, Switzerland, pages 77--96. Springer-Verlag, 1991.

....DRASTIC has been designed to support exactly these kinds of change by using zones and zone contracts. 8.4 Schema Evolution and Versioning Schema evolution and versioning are two different approaches to dynamically changing a database schema. Schema evolution ( BKKK87, MSOP86, LH90, BBB 88, Bar91, TS92] systems tend to focus on how changes to the schema are described and ways of ensuring that changes do not invalidate the database contents. Versioning approaches ( BB88, SZ86, Zdo90, MS93, Cla92, Bra93] focus on how to allow multiple versions of an object to co exist at run time. The ....

G. Barbedette. Schema Modifications in the LISPO2 Persistent Object-Oriented Language. In P. America, editor, Proceedings of the ECOOP '91 European Conference on Object-oriented Programming, LNCS 512, pages 77--96, Geneva, Switzerland, July 1991. Springer-Verlag.

....convert the data from its old format to its new format using a special purpose data translation language, but there is little tool support to assist in this process. Several researchers have investigated type evolution in object oriented databases. Orion [BKKK87, KK88] GemStone [PS87] and O 2 [Bar91] are object oriented database systems that provide some evolution support. In these systems, evolution is defined in terms of primitive structural changes isolated to individual type definitions, such as adding instance variables to a class, removing instance variables from a class, and renaming ....

G. Barbedette. Schema modifications in the LISPO 2 persistent object-oriented language. In P. America, editor, Proceedings of ECOOP '91, the Fifth European Conference on ObjectOriented Programming, number 512 in Lecture Notes in Computer Science, Geneva, Switzerland, July 1991. Springer-Verlag.

....addition of other languages will allow us to continue our experimentation with PolySPIN, in an effort to further confirm, or find ways to extend, its generality and applicability. An important problem closely related to interoperability is the problem of type evolution in persistent object systems [2, 1, 15, 17, 18]. Indeed, the type evolution problem can be seen as a special case of interoperability, one in which the need for interoperation arises due to changes in the definitions of one or more data types that have existing persistent instances. We plan to investigate the extension of our interoperability ....

G. Barbedette. Schema modifications in the LISPO 2 persistent object-oriented language. In Proceedings of the Fifth European Conference on Object-Oriented Programming, number 512 in Lecture Notes in Computer Science, Geneva, Switzerland, July 1991.

.... complexity inheritance and encapsulation introduce, class evolution causes a significant impact on the maintenance and testing of an application [10, 20, 54] While evolution has been well researched, the focus has been on maintaining the structural consistency of objects existing in a database [4, 14, 50, 51]. The impact of evolution on existing programs remains to be fully analyzed. Adaptive software [55, 42] refers to a model of object oriented software development in which functional program components are designed to be flexible to changes in the class structure. Behavior is implemented based on a ....

Gilles Barbedette. Schema modifications in the lispo 2 persistent object-oriented language. In European Conference on Object-Oriented Programming. Springer-Verlag, 1991.

....with other specifications of the same domain. This may involve modifications to the database objects as well as application programs, in some way ensuring that these may become compatible. In general, there are two different approaches to SMM. The schema evolution approach [BKKK87, PS87, LH90, Bar91] regards modifications as corrective, and the primary concern is how the impacts of change affect database objects so that these are coerced to comply with the most recent specification of its class. Application programs must always be upgraded and recompiled in accordance with the most recent ....

.... of the property dimension of modeling, usually discussing changes only at the class level (rather than schema) and assuming objects classify in the same way in different contexts (with no ability to evolve) Most evolution oriented SMM approaches (e.g. ORION [BKKK87] GemStone [PS87] and O 2 [Bar91] assume a restricted taxonomy of valid changes, along with predefined rules for how the object base is to be affected. OTGen [LH90] allows for the specification of schema level modifications as well, but still upgrades the database to make all objects comply with the most recent specification ....

Gilles Barbedette. Schema Modifications in the LISPO 2 Persistent Object-Oriented Language. In ECOOP '91. European Conference on Object-Oriented Programming, Geneva, Switzerland, pages 77--96. Springer-Verlag, 1991.

....better structured systems, evolving these systems continues to be a challenge. The effects of schema evolution on existing classes and objects have been well studied and described, 1] 13] 14] 9] while the issues relevant to maintaining object behavior have only begun to be addressed. 5] [2], 6] Utilizing a high level descriptive language to define class structure and behavior enables development of systems which can support evolution, as well as maintain consistency between documentation and code. Use of a CASE tool to define the system and generate the corresponding code should ....

Gilles Barbedette. Schema modifications in the lispo 2 persistent object-oriented language. In European Conference on Object-Oriented Programming ECOOP'91. Springer-Verlag, 1991.

....Solutions are compared in both models using C and CLOS as examples. 1 Introduction Schema evolution and transformations have recently received increasing attention in the literature in both the area of object oriented languages and especially in the area of object oriented database systems: [Opd92, Ber92, Ber91, Cas91, CPLZ91, DZ91, Bar91, LH90, AH88, BKKK87, PS87, SZ86]. Most of this work has been done from the object oriented database point of view where the focus is naturally on the structural, rather than behavioral, aspects of the evolving schema. Systems such as ORION [BKKK87] GemStone [PS87] and OTGen [LH90] guarantee the correctness of the performed ....

Gilles Barbedette. Schema modifications in the lispo 2 persistent objectoriented language. In Pierre America, editor, European Conference on Object-Oriented Programming, pages 77--96, Geneva, Switzerland, July 1991. Springer Verlag, Lecture Notes in Computer Science.

.... Sons 1. Introduction Class organizations (schemas) evolve over the life cycle of object oriented systems for a variety of reasons. This issue has recently been a subject of increasing attention in the literature of both object oriented languages and especially object oriented database systems: [22, 19, 29, 8, 5, 10, 11, 12, 4, 21, 1, 3, 30, 34]. One of the most common forms of evolution involves the extension of an existing schema by addition of new classes of objects or the addition of attributes to the original objects. Sometimes class structures are reorganized even when the set of objects is unchanged. In this case the reorganiza ....

Gilles Barbedette. Schema modifications in the lispo 2 persistent object-oriented language. In Pierre America, editor, European Conference on Object-Oriented Programming,pages 77--96,Geneva, Switzerland, July 1991. Springer Verlag, Lecture Notes in Computer Science.

....must address the issue of adequate testing during component reuse. Class evolution has significant impact on the maintenance and testing of an application. While class evolution has been well researched, the focus has been on maintaining the structural consistency of objects in a database[1, 5]. Adaptive Software as defined by Lieberherr, Palsberg and Xiao [20, 27] refers to a model of software development in which program components are designed to be flexible to changes in class structure. Behavior is implemented based on a set of high level constraints. The class constraints define a ....

Gilles Barbedette. Schema modifications in the lispo 2 persistent object-oriented language. In European Conference on Object-Oriented Programming. Springer-Verlag, 1991.

No context found.

Barbedette, G.: Schema modifications in the LISPO2 persistent object-oriented language. In Proceedings of ECOOP'91 (P. America, ed.), LNCS 512, Geneva, Switzerland, July 1991, Springer-Verlag.

No context found.

Gilles Barbedette. Schema Modifications in the LISPO Persistent Object-Oriented Language. In ECOOP '91. European Conference on Object-Oriented Programming, Geneva, Switzerland, pages 77--96. Springer-Verlag, 1991.

No context found.

G. Barbedette, Schema modifications in the LISPO2 persistent object-oriented language, In ECOOP '91. European Conference on Object Oriented Programming. Proceedings. Springer Verlag, Berlin, Germany, 1991.

No context found.

Gilles Barbedette. Schema modifications in the lispo 2 persistent object-oriented language. In Pierre America, editor, European Conference on Object-Oriented Programming, pages 77--96, Geneva, Switzerland, July 1991. Springer Verlag, Lecture Notes in Computer Science.

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