Schema Evolution publication categorizer

Composition of mappings between schemas is essential to support
schema evolution, data exchange, data integration, and other data
management tasks. In many applications, mappings are given by
embedded dependencies. In this paper, we study the issues involved
in composing such mappings.
Our algorithms and results extend those of Fagin et al. [8] who
studied composition of mappings given by several kinds of constraints.
In particular, they proved that full source-to-target tuplegenerating
dependencies (tgds) are closed under composition, but