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Reliability of Answers to Queries in Relational Databases
June 1991 (vol. 3 no. 2)
pp. 245-251

The author studies the problem of determining the reliability of answers to queries in a relational database system, where the information in the database comes from various sources with varying degrees of reliability. An extended relational model is proposed in which each tuple in a relation is associated with an information source vector which identifies the information source(s) that contributed to that tuple. The author shows how relational algebra operations can be extended, and implemented using information source vectors, to calculate the vector corresponding to each tuple in the answer to a query, and hence, to identify information source(s) contributing to each tuple in the answer. This also enables the database system to calculate the reliability of each tuple in the answer to a query as a function of the reliability of information sources.

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Index Terms:
relational database system; extended relational model; tuple; information source vector; relational algebra operations; database system; reliability; database theory; information retrieval systems; relational databases
F. Sadri, "Reliability of Answers to Queries in Relational Databases," IEEE Transactions on Knowledge and Data Engineering, vol. 3, no. 2, pp. 245-251, June 1991, doi:10.1109/69.88004
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