Schema Evolution through Changes to ER Diagrams

Chien-Tsai Liu, Panos K. Chrysanthis, S.-K. Chang

Research output: Contribution to journalArticle

Abstract

In order to meet the requirements of new database applications while, at the same time, continue to support existing applications, database systems need to be able to cope with changing database schemas and maintain consistency between instances created under different schemas.
This paper presents an approach to schema evolution through changes to the Entity-Relationship (ER) schema of a database. In order to facilitate changes to the ER schema, we enhanced the basic constructs of ER diagrams with constructs that specify versions of entity and relationship types, and relationships between attributes in different versions. This approach has the advantage of being graphic-oriented and closer to the designer's perception of data rather than to the logical database schema which describes how data are stored in the database. The under-lying database structure is re-organized, if necessary, to accommodate new data without changes affecting existing objects. In this way and through the construction of views, modifications of existing programs are avoided while all objects in the database are accessible to all application programs, both new and old.
Original languageEnglish
JournalJournal of Information Science and Engineering
Volume9
Publication statusPublished - 1993

Fingerprint

Application programs

Cite this

Schema Evolution through Changes to ER Diagrams. / Liu, Chien-Tsai; Chrysanthis, Panos K.; Chang, S.-K.

In: Journal of Information Science and Engineering, Vol. 9, 1993.

Research output: Contribution to journalArticle

Liu, Chien-Tsai ; Chrysanthis, Panos K. ; Chang, S.-K. / Schema Evolution through Changes to ER Diagrams. In: Journal of Information Science and Engineering. 1993 ; Vol. 9.
@article{b2be3a0850ac467da561b0bc16340e5c,
title = "Schema Evolution through Changes to ER Diagrams",
abstract = "In order to meet the requirements of new database applications while, at the same time, continue to support existing applications, database systems need to be able to cope with changing database schemas and maintain consistency between instances created under different schemas.This paper presents an approach to schema evolution through changes to the Entity-Relationship (ER) schema of a database. In order to facilitate changes to the ER schema, we enhanced the basic constructs of ER diagrams with constructs that specify versions of entity and relationship types, and relationships between attributes in different versions. This approach has the advantage of being graphic-oriented and closer to the designer's perception of data rather than to the logical database schema which describes how data are stored in the database. The under-lying database structure is re-organized, if necessary, to accommodate new data without changes affecting existing objects. In this way and through the construction of views, modifications of existing programs are avoided while all objects in the database are accessible to all application programs, both new and old.",
author = "Chien-Tsai Liu and Chrysanthis, {Panos K.} and S.-K. Chang",
year = "1993",
language = "English",
volume = "9",
journal = "Journal of Information Science and Engineering",
issn = "1016-2364",
publisher = "Institute of Information Science",

}

TY - JOUR

T1 - Schema Evolution through Changes to ER Diagrams

AU - Liu, Chien-Tsai

AU - Chrysanthis, Panos K.

AU - Chang, S.-K.

PY - 1993

Y1 - 1993

N2 - In order to meet the requirements of new database applications while, at the same time, continue to support existing applications, database systems need to be able to cope with changing database schemas and maintain consistency between instances created under different schemas.This paper presents an approach to schema evolution through changes to the Entity-Relationship (ER) schema of a database. In order to facilitate changes to the ER schema, we enhanced the basic constructs of ER diagrams with constructs that specify versions of entity and relationship types, and relationships between attributes in different versions. This approach has the advantage of being graphic-oriented and closer to the designer's perception of data rather than to the logical database schema which describes how data are stored in the database. The under-lying database structure is re-organized, if necessary, to accommodate new data without changes affecting existing objects. In this way and through the construction of views, modifications of existing programs are avoided while all objects in the database are accessible to all application programs, both new and old.

AB - In order to meet the requirements of new database applications while, at the same time, continue to support existing applications, database systems need to be able to cope with changing database schemas and maintain consistency between instances created under different schemas.This paper presents an approach to schema evolution through changes to the Entity-Relationship (ER) schema of a database. In order to facilitate changes to the ER schema, we enhanced the basic constructs of ER diagrams with constructs that specify versions of entity and relationship types, and relationships between attributes in different versions. This approach has the advantage of being graphic-oriented and closer to the designer's perception of data rather than to the logical database schema which describes how data are stored in the database. The under-lying database structure is re-organized, if necessary, to accommodate new data without changes affecting existing objects. In this way and through the construction of views, modifications of existing programs are avoided while all objects in the database are accessible to all application programs, both new and old.

M3 - Article

VL - 9

JO - Journal of Information Science and Engineering

JF - Journal of Information Science and Engineering

SN - 1016-2364

ER -