NeT & CoT: Translating Relational Schemas to XML Schemas using Semantic Constraints

Abstract

Two algorithms, called NeT and CoT, to translate relational schemas to XML schemas using various semantic constraints are presented. The XML schema representation we use is a language-independent formalism named XSchema, that is both precise and concise. A given XSchema can be mapped to a schema in any of the existing XML schema language proposals. Our proposed algorithms have the following characteristics: (1) NeT derives a nested structure from a flat relational model by repeatedly applying the nest operator on each table so that the resulting XML schema becomes hierarchical, and (2) CoT considers not only the structure of relational schemas, but also semantic constraints such as inclusion dependencies during the translation. It takes as input a relational schema where multiple tables are interconnected through inclusion dependencies and converts it into a good XSchema. To validate our proposals, we present experimental results using both real schemas from the UCI repository and synthetic schemas from TPC-H.