World Library  
Flag as Inappropriate
Email this Article

Conceptual schema

Article Id: WHEBN0000058267
Reproduction Date:

Title: Conceptual schema  
Author: World Heritage Encyclopedia
Language: English
Subject: Enhanced entity–relationship model, Software analysis pattern, Business semantics management, Data model, Business rule
Collection: Concepts, Data Modeling
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Conceptual schema

A conceptual schema is a high-level description of a business's informational needs. It typically includes only the main concepts and the main relationships among them. Typically this is a first-cut model, with insufficient detail to build an actual database.[1]

Contents

  • Overview 1
  • Example relationships 2
  • Data structure diagram 3
    • See also 3.1
  • References 4
  • Further reading 5
  • External links 6

Overview

A conceptual schema or conceptual organization (entity classes), about which it is inclined to collect information, and characteristics of (attributes) and associations between pairs of those things of significance (relationships).

Because a conceptual schema represents the semantics of an organization, and not a database design, it may exist on various levels of abstraction. The original ANSI four-schema architecture began with the set of external schemas that each represent one person's view of the world around him or her. These are consolidated into a single conceptual schema that is the superset of all of those external views. A data model can be as concrete as each person's perspective, but this tends to make it inflexible. If that person's world changes, the model must change. Conceptual data models take a more abstract perspective, identifying the fundamental things, of which the things an individual deals with are just examples.

The model does allow for what is called inheritance in object oriented terms. The set of instances of an entity class may be subdivided into entity classes in their own right. Thus, each instance of a sub-type entity class is also an instance of the entity class's super-type. Each instance of the super-type entity class, then is also an instance of one of the sub-type entity classes.

Super-type/sub-type relationships may be exclusive or not. A methodology may require that each instance of a super-type may only be an instance of one sub-type. Similarly, a super-type/sub-type relationship may be exhaustive or not. It is exhaustive if the methodology requires that each instance of a super-type must be an instance of a sub-type.

Example relationships

  • Each PERSON may be the vendor in one or more ORDERS.
  • Each ORDER must be from one and only one PERSON.
  • PERSON is a sub-type of PARTY. (Meaning that every instance of PERSON is also an instance of PARTY.)
  • Each EMPLOYEE may have a supervisor who is also an EMPLOYEE.

Data structure diagram

Data Structure Diagram.

A data structure diagram (DSD) is a data model or diagram used to describe conceptual data models by providing graphical notations which document entities and their relationships, and the constraints that bind them.

See also

References

  1. ^ "Data Modelling Tutorial", Stefano Grazioli, University of Virginia, http://webs.comm.virginia.edu/Grazioli/MSMITMod1/DataModelingTutorial/DMTutorialHome.html retrieved 20 February 2014

Further reading

  • Perez, Sandra K., & Anthony K. Sarris, eds. (1995) Technical Report for IRDS Conceptual Schema, Part 1: Conceptual Schema for IRDS, Part 2: Modeling Language Analysis, X3/TR-14:1995, American National Standards Institute, New York, NY.

External links

  • A different point of view, as described by the "agile" community
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.