Schema Evolution publication categorizer

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

The concept of “model” is today considered as a promising technology in domains such as
data and software engineering. In the field of model engineering, models are now viewed as
firts-class entities. This new approach makes it possible to envision the integration of models
into engineering processes. Such an integration will however require a set of dedicated tools
enabling to perform standard model operations onto handled models. We strongly believe that,
in order to achieve usability for large communinities of users, model-based tools have to rely

XML brought several important qualities to data representation. Through the usage of tags, it
combined schema and data information. Tag nesting enabled a simple representation of hierarchical
relations. Such enrichments sparked off a new wave of research on how to improve querying
and searching of data within XML documents.
The Internet is practically an endless collection of data being used simultaneously by millions
of users. We expect that for a large part, this information will become available in XML. As such,

This technical report describes how IQL queries are processed in the AutoMed heterogeneous data integration system, and also how data migration can be supported.
We start with an outline of the IQL language in Section 2. We then consider in Section 3 an abstract representation of this textual IQL and describe the ASG class that implements this abstract representation.

We define a general model for database schemas which is basically functional and supports specialisation relationships. Despite it's simplicity, our model is very general and expressive, so that database schemas and instances arising from a number of other data models can be translated into the model.

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.

The days when a company could take its system offline for any kind of maintenance are rapidly disappearing. As businesses become global and move toward e-commerce, systems now have to be highly available because the cost of outage for corporations involved in e-commerce can easily reach millions of dollars per hour. Today, it is unlikely that the customer will come back if your systems are unavailable, they will simply give that business to your competitor whose systems are online.

We study a collection of heterogeneous XML databases maintaining similar and related information, exchanging data via a peer to peer overlay network. In this setting, a mediated global schema is unrealistic. Yet, users/applications wish to query the databases via one peer using its schema. We have recently developed HepToX, a P2P Heterogeneous XML database system. A key idea is that whenever a peer enters the system, it establishes an acquaintance with a small number of peer databases, possibly with different schema.

Dynamic schema evolution is the ability of the database schema to evolve by incorporating changes to its structure without loss of existing data and without significantly affecting the day-to-day operations of the database. A very large body of literature exists today reflecting the extensive work addressing schema evolution and its management. Schema evolution has three well-defined and inter-related activities: core schema evolution, version management, and application management.

It is clear that XML schemas will evolve over time and it is important to capture the
schema’s version. This write-up summarizes two cases for schema changes and some
options for schema versioning. It then provides some ‘best practice’ guidelines for XML
schema versioning.

Introduction

API versioning is a common problem in the design of any distributed system, and Web services are unfortunately no exception. In this article, Kyle Brown and Michael Ellis will outline the scope of the versioning difficulties facing Web services developers, provide some template solutions, and discuss architectures and best practices for addressing the problem.