Logical and physical support for heterogeneous data Sihem Amer-Yahia, Mary F. Fernandez, Rick Greer, and Divesh Srivastava   View Paper (PDF)   Return to XML schemas: integration and translation Abstract Heterogeneity arises naturally in virtually all real-world data. This paper presents evolutionary extensions to a relational database system for supporting three classes of data heterogeneity: variational, structural and annotational heterogeneities. We define these classes and show the impact of these new features on data storage, data-access mechanisms, and the data-description language. Since XML is an important source of heterogeneity, we describe how the system automatically utilizes these new features when storing XML documents. DiSC'03 © 2003 Association for Computing Machinery