Encyclopedia of Database Systems

2018 Edition
| Editors: Ling Liu, M. Tamer Özsu

Inconsistent Databases

  • Leopoldo BertossiEmail author
Reference work entry
DOI: https://doi.org/10.1007/978-1-4614-8265-9_1242


An inconsistent database is a database instance that does not satisfy those integrity constraints that have been declared together with the schema of the database.

Historical Background

Already in the classical and seminal paper by E. F. Codd [5] on the relational data model it is possible to find the notions of integrity constraint and consistency of a database. The idea of consistent query answering, consisting in characterizing and computing semantically correct answers to queries in inconsistent databases, was explicitly introduced in [1].


A database can be seen as a model, i.e., as a simplified, abstract description, of an external reality. In the case of relational databases, one starts by choosing certain predicates of a prescribed arity. The schema of the database consists of this set of predicates, possibly attributes, which can be seen as names for the arguments of the predicates, together with an indication of the domains where the attributes can take...

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Recommended Reading

  1. 1.
    Arenas M, Bertossi L, Chomicki J. Consistent query answers in inconsistent databases. In: Proceedings of the 18th ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems; 1999. p. 68–79.Google Scholar
  2. 2.
    Bertossi L. Consistent query answering in databases. ACM SIGMOD Rec. 2006;35(2):68–76.CrossRefGoogle Scholar
  3. 3.
    Bertossi L, Chomicki J. Query answering in inconsistent databases. In: Logics for emerging applications of databases. Berlin: Springer; 2003. p. 43–83.Google Scholar
  4. 4.
    Chomicki J. Consistent query answering: five easy pieces. In: Proceedings of the 11th International Conference on Database Theory; 2007. p. 1–17.Google Scholar
  5. 5.
    Codd EF. A relational model of data for large shared data banks. Commun ACM. 1970;13(6):377–87.zbMATHCrossRefGoogle Scholar
  6. 6.
    Enderton H. A mathematical introduction to logic. 2nd ed. New York: Academic; 2001.zbMATHGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Carleton UniversityOttawaCanada

Section editors and affiliations

  • Leonid Libkin
    • 1
  1. 1.School of InformaticsUniversity of EdinburghEdinburghUK