The Database Group @ University of Toronto  The ToMAS Project
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  Project Description
 
 ToMAS is a tool for managing schema mappings. ToMAS manages queries, views and schema mappings such as those created by mapping tools like Clio external link
 
 To achieve interoperability, modern information systems and e-commerce applications use mappings to translate data from one representation to another. In dynamic environments like the Web, data sources may change not only their data but also their schemas, their semantics, and their query capabilities. Such changes must be reflected in the mappings. Mappings left inconsistent by a schema change have to be detected and updated. As large, complicated schemas become more prevalent, and as data is reused in more and more applications, manually maintaining mappings (even simple mappings like view definitions) is becoming impractical. We present a novel framework and tool, ToMAS, for automatically adapting mappings as schemas evolve. Our approach considers not only local changes to a schema, but also changes that may affect and transform many components of a schema. We consider a comprehensive class of mappings for relational and XML schemas with choice types and (nested) constraints. Our algorithm detects mappings affected by a structural or constraint change and generates all the rewritings that are consistent with the semantics of the mapped schemas. Our approach explicitly models mapping choices made by a user and maintains these choices, whenever possible, as the schemas and mappings evolve. We describe an implementation of a mapping management and adaptation tool based on these ideas and present a case study using our tool to manage mappings used in a physical DB design tool.
 
  People
 
 
  Publications
 
  • Representing and Querying Data Transformations
    Yannis Velegrakis, Renée J. Miller and John Mylopoulos.
    In Proceedings of the International Conference on Data Engineering (ICDE), 2005.
  • ToMAS: a System for Adapting Mappings while Schemas Evolve
    Yannis Velegrakis, Renée J. Miller, Lucian Popa and John Mylopoulos.
    System Demonstration, International Conference on Data Engineering (ICDE), 2004.
  • Preserving Mapping Consistency under Schema Changes
    Yannis Velegrakis, Renée J. Miller and Lucian Popa.
    In the International Journal on Very Large Data Bases (VLDB Journal), 14(3) p.274-293, 2004.
  • ToMAS: Mapping Adaptation under Evolving Schemas
    Yannis Velegrakis, Renée J. Miller, Lucian Popa and John Mylopoulos.
    In Proceedings of the Second Hellenic Symposium on Data Management, 2003.
  • Mapping Adaptation under Evolving Schemas
    Yannis Velegrakis, Renée J. Miller and Lucian Popa.
    In Proceedings of the International Conference on Very Large Databases (VLDB), 2003.
  • Translating Web Data
    Lucian Popa, Yannis Velegrakis, Renée J. Miller, Mauricio Hernández and Ron Fagin.
    In Proceedings of the International Conference on Very Large Databases (VLDB), 2002.
  • Translating Web Data
    Lucian Popa, Yannis Velegrakis, Renée J. Miller, Mauricio Hernández and Ron Fagin.
    Technical Report CSRI 441, University of Toronto, 2002.
  • Mapping XML and Relational Schemas with CLIO
    Lucian Popa, Mauricio A. Hernández, Yannis Velegrakis and Renée J. Miller.
    System Demonstration, IEEE Data Engineering Conference, 2002.
 
Copyright © 2006 The Database Group @ University of Toronto | Last Updated July 11, 2007