Holistic constraint-preserving transformation from relational schema into XML schema

In this paper, we propose a holistic scheme of transforming a relational schema into an XML Schema with integrity constraints preserved. This scheme facilitates constructing a schema for the published XML views of relational data. With this schema, users are able to issue qualified queries against XML views, and discover update anomalies in advance before propagating the view updates into relational database. Compared to the previous work which splits the transformation process into two steps, we establish a holistic solution to directly transform a relational schema into an XML Schema without building a reference graph. We achieve this by classifying the underlying relations in a more concise and effective way, and applying the converting rules wisely. The rules are also devised to be more compact and less complicated in contrast to those in our previous work. Finally, we manage to crack another hard nut which was seldom touched before, i.e. converting circularly referenced relations into recursive XML Schema.