Encyclopedia of Database Systems

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

Safety and Domain Independence

  • Rodney Topor
Reference work entry
DOI: https://doi.org/10.1007/978-1-4614-8265-9_1255

Synonyms

Finiteness

Definition

The values in the relations of a relational database are elements of one or more underlying sets called domains. In practical applications, a domain may be infinite, e.g., the set of natural numbers. In this case, the value of a relational calculus query when applied to such a database may be infinite, e.g., {n| n ≥ 10}. A query Q is called finite if the value of Q when applied to any database is finite.

Even when the database domains are finite, all that is normally known about them is that they are some finite superset of the values that occur in the database. In this case, the value of a relational calculus query may depend on such an unknown domain, e.g., {x ∣ ∀ yR(x, y)}. A query Q is called domain independent if the value of Q when applied to any database is the same for any two domains containing the database values or, equivalently, if the value of Q when applied to a database contains only values that occur in the database.

The term safequery...

This is a preview of subscription content, log in to check access.

Recommended Reading

  1. 1.
    Abiteboul R, Hull R, Vianu V. Foundations of databases, chapter 5. Reading: Addison-Wesley; 1995. p. 70–104.Google Scholar
  2. 2.
    Benedikt M, Libkin L. Safe constraint queries. SIAM J Comput. 2000;29(5):1652–82.MathSciNetzbMATHCrossRefGoogle Scholar
  3. 3.
    DiPaola RA. The recursive unsolvability of the decision problem for the class of definite formulas. J ACM. 1969;16(2):324–7.CrossRefGoogle Scholar
  4. 4.
    Escobar-Molano M, Hull R, Jacobs D. Safety and translation of calculus queries with scalar functions. In: Proceedings of the 12th ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems; 1993. p. 253–64.Google Scholar
  5. 5.
    Hull R, Su J. Domain independence and the relational calculus. Acta Inform. 1994;31(6):513–24.MathSciNetzbMATHCrossRefGoogle Scholar
  6. 6.
    Kifer M. On Safety, Domain Independence, and Capturability of Database Queries (Preliminary Report). In: Proceedings of the 3rd International Conferences on Data and Knowledge Bases; 1988. p. 405–15.Google Scholar
  7. 7.
    Stolboushkin AP, Taitslin MA. Finite queries do not have effective syntax. Inf Comput. 1996;153(1):99–116.MathSciNetzbMATHCrossRefGoogle Scholar
  8. 8.
    Suciu D. Domain-independent queries on databases with external functions. Theor Comput Sci. 1998;190(2):279–315.MathSciNetzbMATHCrossRefGoogle Scholar
  9. 9.
    Topor RW. Domain independent formulas and databases. Theor Comput Sci. 1987;52(3):281–306.MathSciNetzbMATHCrossRefGoogle Scholar
  10. 10.
    Ullman JD. Principles of database and knowledge-base systems Volume I, Sections 3.2 and 3.8. Rockville: Computer Science Press; 1988. p. 100–6.Google Scholar
  11. 11.
    Vardi MY. The decision problem for database dependencies. Inf Process Lett. 1981;13(5):251–4.MathSciNetzbMATHCrossRefGoogle Scholar
  12. 12.
    Van Gelder A, Topor RW. Safety and translation of relational calculus aueries. ACM Trans Database Syst. 1981;16(2):235–78.CrossRefGoogle Scholar

Copyright information

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

Authors and Affiliations

  1. 1.Griffith UniversityNathanAustralia

Section editors and affiliations

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