Database Systems (TODS)


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ACM Transactions on Database Systems (TODS), Volume 33 Issue 2, June 2008

Conditional functional dependencies for capturing data inconsistencies
Wenfei Fan, Floris Geerts, Xibei Jia, Anastasios Kementsietsidis
Article No.: 6
DOI: 10.1145/1366102.1366103

We propose a class of integrity constraints for relational databases, referred to as conditional functional dependencies (CFDs), and study their applications in data cleaning. In contrast to traditional functional dependencies (FDs) that...

Metric space similarity joins
Edwin H. Jacox, Hanan Samet
Article No.: 7
DOI: 10.1145/1366102.1366104

Similarity join algorithms find pairs of objects that lie within a certain distance ε of each other. Algorithms that are adapted from spatial join techniques are designed primarily for data in a vector space and often employ some form of a...

Cache-oblivious databases: Limitations and opportunities
Bingsheng He, Qiong Luo
Article No.: 8
DOI: 10.1145/1366102.1366105

Cache-oblivious techniques, proposed in the theory community, have optimal asymptotic bounds on the amount of data transferred between any two adjacent levels of an arbitrary memory hierarchy. Moreover, this optimal performance is achieved without...

Approximate continuous querying over distributed streams
Graham Cormode, Minos Garofalakis
Article No.: 9
DOI: 10.1145/1366102.1366106

While traditional database systems optimize for performance on one-shot query processing, emerging large-scale monitoring applications require continuous tracking of complex data-analysis queries over collections of physically distributed streams....

Repair localization for query answering from inconsistent databases
Thomas Eiter, Michael Fink, Gianluigi Greco, Domenico Lembo
Article No.: 10
DOI: 10.1145/1366102.1366107

Query answering from inconsistent databases amounts to finding “meaningful” answers to queries posed over database instances that do not satisfy integrity constraints specified over their schema. A declarative approach to this problem...

Quasi-inverses of schema mappings
Ronald Fagin, Phokion G. Kolaitis, Lucian Popa, Wang-Chiew Tan
Article No.: 11
DOI: 10.1145/1366102.1366108

Schema mappings are high-level specifications that describe the relationship between two database schemas. Two operators on schema mappings, namely the composition operator and the inverse operator, are regarded as especially important. Progress...

On computing temporal aggregates with range predicates
Donghui Zhang, Alexander Markowetz, Vassilis J. Tsotras, Dimitrios Gunopulos, Bernhard Seeger
Article No.: 12
DOI: 10.1145/1366102.1366109

Computing temporal aggregates is an important but costly operation for applications that maintain time-evolving data (data warehouses, temporal databases, etc.) Due to the large volume of such data, performance improvements for temporal aggregate...