Towards Evolving Constraints in Data Transformation for XML Data Warehousing

Transformation of data is considered as one of the important tasks in data warehousing and data integration. With the massive use of XML as data representation and exchange format over the web in recent years, transformation of data in XML for integration purposes becomes necessary. In XML data transformation, a source schema and its conforming data is transformed to a target schema. Often, source schema is designed with constraints and the target schema also has constraints for data semantics and consistency. Thus, there is a need to see whether the target constraints are implied from the source constraints in data transformation. Towards this problem, we define two important XML constraints namely XML key and XML functional dependency(XFD). We then use important transformation operations to see if the source constraints are satisfied by the source document, then the target constraints are also satisfied by the target document. Our study is towards the utilization of constraints data integration and data warehousing in XML.