Alberto O. Mendelzon

Alberto O. Mendelzon was an Argentine-Canadian computer scientist who died on June 16, 2005.

Alberto Mendelzon was born in Buenos Aires, Argentina. He graduated from the University of Buenos Aires in 1973. He then received a Ph.D. degree from Princeton University in 1979, where his advisor was Jeffrey Ullman. After that he was a post-doctoral fellow at the IBM T.J. Watson Research Center for a year before joining the faculty of the University of Toronto in 1980.

He was one of the pioneers who helped to lay the foundations of relational databases. His early work on database dependencies has been influential in both the theory and practice of data management. He has made fundamental contributions in the areas of graphical query languages, knowledge-base systems, and on-line analytic processing. His work has provided the foundation for languages used to query the structure of the web.

Mendelzon established some of the earliest results on using the relational data model. Together with his thesis advisor, Jeffrey Ullman, and fellow Princeton students, including David Maier and Yehoshua Sagiv, he co-authored a number of influential papers that laid out the fundamental issues and approaches for relational databases. In a now-famous paper (Maier, Mendelzon and Sagiv, TODS 1979), he introduced the chase, a method for testing implication of data dependencies that is now of widespread use in the database theory literature. This work has been highly influential: it is used, directly or indirectly, on an everyday basis by people who design databases, and it is used in commercial systems to reason about the consistency and correctness of a data design. New applications of the chase in meta-data management and data exchange are still being discovered.

In the 1980s, Mendelzon began an important line of work on graphical query languages. His work has been called prescient as it began before the World Wide Web, and nonetheless established many of the scientific principles required for designing languages to query the Web.

More recently, Mendelzon was a central figure in the work on view-based querying. Starting with the innovative LMSS95 paper (Levy, Mendelzon, Sagiv, and Srivastava, PODS 1995) that introduced the problem of answering queries using views, Alberto Mendelzon made several important contributions to the emerging area of view-based modeling and processing.

His research was central to the development of many areas of database research such as database design, semantic query optimization, graphical query languages, and querying web data. In addition, he also made important contributions to recursive query languages, on-line analytic processing, similarity-based queries, data warehouses and view maintenance, algorithms for computing web page reputations, and indexing of XML data.

Mendelzon was an active member of both the database theory and database systems research communities. He served as the PC Chair for ACM PODS in 1991 and as General Chair in both 1997 and 1998. He served as PC Chair for VLDB in 1992, and as a member of the SIGMOD Executive Committee from 1998 to 2001. He was a member of the Royal Society of Canada.