Encyclopedia of Database Systems

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

Daplex

  • Tore Risch
Reference work entry
DOI: https://doi.org/10.1007/978-1-4614-8265-9_1107

Definition

Daplex is a query language based on a functional data model [1] with the same name. The Daplex data model represents data in terms of entities and functions. The Daplex data model is close to the entity-relationship (ER) model with the difference that relationships between entities in Daplex have a logical direction, whereas ER relationships are directionless. Unlike ER entities, relationships, and properties are all represented as functions in Daplex. Also, entity types are defined as functions without arguments returning sets of a built-in type ENTITY. The entity types are organized in a type/subtype hierarchy. Functions represent properties of entities and relationships among entities. Functions also represent derived information. Functions may be set-valued and are invertible. The database is represented as tabulated function extents. Database updates change the function extents.

The Daplex query language has been very influential for many other query languages, both...

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Recommended Reading

  1. 1.
    Gray PMD, Kerschberg L, King PJH, Poulovassilis A, editors. The functional approach to data management. Berlin: Springer; 2004.Google Scholar
  2. 2.
    Landers T, Rosenberg RL. An overview of multibase. In: Proceedings of the 2nd International Symposium on Distributed Databases; 1982. p. 153–84.Google Scholar
  3. 3.
    Shipman DW. The functional data model and the data language DAPLEX. ACM Trans Database Syst. 1981;6(1):140–73.CrossRefGoogle Scholar

Copyright information

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

Authors and Affiliations

  1. 1.Department of Information TechnologyUppsala UniversityUppsalaSweden

Section editors and affiliations

  • Tore Risch
    • 1
  1. 1.Dept. of Inf. TechnologyUppsala Univ.UppsalaSweden