PODS

This volume contains the proceedings of the Twenty-fourth ACM SIGMOD-SIGACT-SIGART Symposium on Principles of Database Systems (PODS 2005), held in Baltimore, USA, on June 13-15, 2005 in conjunction with the 2005 ACM SIGMOD International Conference on Management of Data. It consists of a paper based on the invited talk by Phokion Kolaitis, a paper based on the invited tutorial by Monica Lam, and 32 contributed papers that were selected by the program committee for presentation at the symposium.

The program committee has selected the contributed papers from 157 submissions. Some of the papers are "extended abstracts" and are preliminary reports on work in progress. While the program committee has read them carefully and discussed them intensively, they have not been formally refereed. It is expected that much of the research described in these papers will be published in detail in computer science journals, where they will go through a formal review.

The program committee selected two papers for the PODS 2005 Best Paper Award: <i>XML Data Exchange: Consistency and Query Answering</i> by Marcelo Arenas and Leonid Libkin, and <i>On the complexity of division and set joins in the relational algebra</i> by Dirk Leinders and Jan Van den Bussche, and also selected <i>Security Analysis of Cryptographically Controlled Access to XML Documents</i> by Martin Abadi and Bogdan Warinschi for the PODS 2005 Best Newcomer Award. Warmest congratulations to the authors.

This volume is dedicated to the memory of Seymour Ginsburg, one of the great pioneers of theoretical computer science and database theory who has influenced the career of many distinguished researchers and educators.