Schema Evolution publication categorizer

Schema evolution is of two kinds: (a) those requiring instance transformation because the application is simpler to develop when it works only with one version of the schema, and (b) those in which the old data must be preserved and instance transformation must be avoided. The latter is important in practice but has received scant attention in the literature. Data conforming to multiple versions of the XML schema must be maintained, indexed, and manipulated using the same query. Microsoft’s SQL Server 2005 introduces XML schema collections to address both types of schema evolution.

Many data integration solutions in the market today include tools for schema mapping, to help users visually relate elements of different schemas. Schema elements are connected with lines, which are interpreted as mappings, i.e. high-level logical expressions capturing the relationship between source and target data-sets; these are compiled into queries and programs that convert source-side data instances into target-side instances.

In this paper, we illustrate a preliminary approach to the
translation of Web data between heterogeneous formats. This work fits
into a larger pro ject whose aim is the development of a tool for the man-
agement of data described according to a large variety of formats used on
the Web and the (semi)automatic translation of schemes and instances
from one model to another. Data translations operate over XML repre-
sentations of instances and rely on a uniform representation of models
that we call metamodel. The metamodel shows structural diversities and