Database systems often use XML schema to describe the format of valid XML documents. Usually, this format is determined when the system is designed. Sometimes, in an already functioning system, a need arises to change the XML schemas. In such a situation, the system has to transform the old XML documents so that they conform to the new format and that as little information as possible is lost in the process. This process is called schema evolution.We have implemented an XML schema transformation toolkit within IBM Master Data Management Server (MDM). MDM uses XML documents to describe products that an enterprise may be offering to its clients. In this work we focus on evolving schemas rather than on integrating separate or heterogeneous data sources. Our solution includes an extendible schema matching algorithm that was designed with evolving XML schemas in mind and takes advantage of hierarchical structure of XML. It also includes a data transformation and migration method appropriate for environments where migration is performed in an abstraction layer above the DBMS. Finally, we describe a novel way of extending an XSLT editor with an XSLT visualization feature to allow the user's input and evaluation of the transformation.

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Abstract. This work presents a case study of a migration of attributebased access control enforcement from the application to the database tier. The proposed migration aims to improve the security and simplify the audit of the enterprise system by enforcing information protection principles of the least privileges and the least common mechanism. We explore the challenges of such migration and implement it in an industrial setting in a context of master data management where data security, privacy and audit are subject to regulatory compliance. Based on our implementation, we propose a general, standards-driven migration methodology.