Schema Evolution publication categorizer

Database and software systems are rarely stable following initial implementation. Although estimates differ, most agree that 50% or more of programmer effort arises as a result of system modifications after implementation [Lientz, B. P. 1983] and facilitating those changes is complicated if large numbers of programs or large quantities of data are involved. Moreover, system modifications that result in changes to database structure are relatively frequent [Sjoberg, D. 1992, Sjoberg, D. 1993].

Background
Ontologies are increasingly used to structure and semantically describe entities of domains, such as genes and proteins in life sciences. Their increasing size and the high frequency of updates resulting in a large set of ontology versions necessitates efficient management and analysis of this data.

Results

In den Lebenswissenschaften haben sich Ontologien in den letzten Jahren auf breiter Front durchgesetzt und sind in vielen Anwendungs- und Analyseszenarien kaum mehr wegzudenken. So etablierten sich nach und nach immer mehr domänenspezifische Ontologien, z.B. Anatomie-Ontologien oder Ontologien zur Beschreibung der Funktionen von Genen oder Proteinen. Da das Wissen in den Lebenswissenschaften sich rapide ändert und weiterentwickelt, müssen die entsprechenden Ontologien ständig angepasst und verändert werden, um einen möglichst aktuellen Wissensstand zu repräsentieren.

Supporting legacy applications when the database schema evolves represents a long-standing challenge of practical and theoretical importance. Recent work has produced algorithms and systems that automate the process of data migration and query adaptation; how- ever, the problems of evolving integrity constraints and supporting legacy updates under schema and integrity constraints evolution are significantly more difficult and have thus far remained unsolved.

More and more integration systems use ontologies to solve the problem of semantic heterogeneities between autonomous databases. To automate the integration process, a number of these systems suppose the existence of a shared domain ontology a priori referenced by the local ontologies embedded in the various sources. When the shared ontology evolves over the time, the evolution may concern (i) the ontology level, (2) the local schema level, and/or (3) the contents of sources.

In this paper we present a formal model for the support of temporal schema versions in object-oriented databases. Its definition is partially based on a generic (ODMG compatible) object model and partially introduces new concepts. The proposed model supports all the schema changes which are usually considered in the OODB literature, for which an operational semantics and a formal analysis of their correct behaviour is provided.

The problem of archiving and querying the history of a database is made more complex by the fact that, along with the database content, the database schema also evolves with time.

The W3C XML Schema recommendation defines the structure and data types for XML documents, but lacks explicit support for time-varying XML documents or for a time-varying schema. In previous work we introduced τXSchema, which is an infrastructure and suite of tools to support the creation and validation of time-varying documents, without requiring any changes to XML Schema. In this paper we extend τXSchema to support versioning of the schema itself.

The W3C XML Schema recommendation defines the structure and data types for XML documents.
XML Schema lacks explicit support for time-varying XML documents or for time-varying schemas. An
XML document evolves as it is updated over time or as it accumulates from a streaming data source. A
temporal document records the entire history of a document rather than just its current state or snapshot.
Capturing a document’s evolution is vital to providing the ability to recover past versions, track changes

Ontologies have become very popular in life sciences and other domains. They mostly undergo continuous changes and new ontology versions are frequently released. However, current analysis studies do not consider the ontology changes reflected in different versions but typically limit themselves to a specific ontology version which may quickly become obsolete. To allow applications easy access to different ontology versions we propose a central and uniform management of the versions of different biomedical ontologies.

DEMO PAPER:

Modern information systems, and web information systems in particular, are faced with frequent database schema changes, which generate the necessity to manage such evolution and preserve their history.

The old problem of managing the history of database information is now made more urgent and complex by fast-spreading web information systems. Indeed, systems such as Wikipedia are faced with the challenge of managing the history of their databases in the face of intense database schema evolution. Our PRIMA system addresses this difficult problem by introducing two key pieces of new technology.

Ontologies, are explicit specifications of conceptualisations, and as such
serve as a backbone of many Information Systems (ISs) as knowledge bearing
artefacts representing mainly domain knowledge. As the use of ontologies in
several kinds of ISs increased in the recent years significantly, the question
of how to maintain these ontologies, gained more importance.
Although, there are no sophisticated methods available yet to support
all the aspects of change management for ontologies, it surely is an active
research field. Most of the work has been done under the titles of Ontology

After more than 20 years of research and practice in software configuration management (SCM), constructing consistent configurations of versioned software products still remains a challenge. This article focuses on the version models underlying both commercial systems and research prototypes. It provides an overview and classification of different versioning paradigms and defines and relates fundamental concepts such as revisions, variants, configurations, and changes. In particular, we focus on intensional versioning, that is, construction of versions based on configuration rules.

In this paper, we propose a schema versioning mechanism to manage the schema evolution in temporal object-oriented databases. The schema evolution management uses an object-oriented data model that supports temporal features and versions definition - the Temporal Versions Model - TVM. One interesting feature of our proposal is that TVM is used to control not only the schema versioning, but also the storage of extensional database and propagation of the changes performed on the objects.

Schema evolution is the ability of the database to respond to changes in the real world by allowing the schema to evolve. The multidimensional conditionally evolving schema(MD-CES) is a conceptual model for conditional schema changes, which modify the schema of those tuples that satisfy the change condition. The MD-CES is lossless and preserves schemas, but has an exponential space complexity. In this paper we restrict conditional schema changes to timestamp attributes.

An approach to schema modification management is presented which also takes into concern that alternative schema perspectives seems to be needed, in addition to revision-like changes. The primary goal is to support change transparency when the schema is modified, such that existing application programs and objects need not be affected by changes to the schema. The approach is based on explicitly distinguishing Type (external interface of objects) and Class (object implementation and...

This paper addresses the design of a schema evo-
lution framework enabling an efficient management of
object versions. This framework is based on the adap-
tation and extension of two main schema evolution
approaches, that is the approaches based on schema
modification and those based on schema versioning.
The framework provides an integrated environment to
support different levels of adaptation (such as, modifi-
cation and versioning at the schema level, conversion,
object versioning, and emulation at the instance level).
In addition, we introduce the concept of class/schema

This paper addresses the design of an integrated framework for managing schema evolution. This framework is based on the adaptation and extension of two main schema evolution approaches, namely schema modification and schema versioning. The proposed framework provides an integrated environment to support different database evolution techniques (such as, modification and versions at the schema level, conversion, object versioning, and screening at the instance level).

Integrated engineering environments, based on federated database technology, are, among others, a means to control the integrity of and dependencies between product data created in many different engineering applications. Most of these applications support the management of versions of a product and its parts, continuing the engineers' tradition of keeping different versions of drawings and documents. Consequently, federations in engineering environments have to provide version management on their global layer as well.

Ontologies are often seen as basic building blocks for the SemanticWeb,
as they provide a reusable piece of knowledge about a specific domain. However, those
pieces of knowledge are not static, but evolve over time. Domain changes, adaptations
to different tasks, or changes in the conceptualization require modifications of the ontology.
The evolution of ontologies causes operability problems, which will hamper
their effective reuse. A versioning mechanism might help to reduce those problems,
as it will make the relations between different revisions of an ontology explicit. This

Version control is one of the most important functions which need to be supported in integrated computer-aided design (CAD) systems. In this paper we address a broad spectrum of semantic and operational issues in version control for a public/private distributed architecture of CAD systems. The research issues we address include the semantics of version creation and manipulation, version naming and name binding, and version change notification. We develop solutions to these issues under a unifying framework, and discuss implementation and application interface issues.

In engineering applications, multiple copies of object descriptions have to coexist in a single database. A scheme is proposed that enables users to explicitly deal with these object versions. After introducing a basic version model, the problem of rerouting interobject references on the creation of new versions is solved by providing generic references and user-specific environments. Logical version clusters are introduced that allow for the meaningful grouping of versions. Some remarks on implementation and a comparison with other approaches are also included

XML is designed for the creation of languages based upon self-describing markup. The inevitable evolution of these languages is called versioning. Versioning means adding, deleting, or changing parts of the language. Making versioning work in practice is one of the most difficult problems in computing, with a long history of failed attempts.