TY - GEN
T1 - Database schema evolution through the specification and maintenance of changes on entities and relationships
AU - Liu, Chien Tsai
AU - Chrysanthis, Panos K.
AU - Chang, Shi Kuo
PY - 1994
Y1 - 1994
N2 - A flexible database system needs to support changes to its schema in order to facilitate the requirements of new applications and to support interoperability within a multidatabase system. In this paper, we present an approach to schema evolution through changes to the Entity-Relationship (ER) schema of a database. We enhance the graphical constructs used in ER diagrams, and develop EVER, an EVolutionary ER diagram for specifying the derivation relationships between schema versions, relationships among attributes, and the conditions for maintaining consistent views of programs. Algorithms are presented for mapping the EVER diagram into the underlying database and constructing database views for schema versions. Through the reconstruction of views after database reorganization, changes to an ER diagram can be made transparent to the application programs while all objects in the database remain accessible to the application programs.
AB - A flexible database system needs to support changes to its schema in order to facilitate the requirements of new applications and to support interoperability within a multidatabase system. In this paper, we present an approach to schema evolution through changes to the Entity-Relationship (ER) schema of a database. We enhance the graphical constructs used in ER diagrams, and develop EVER, an EVolutionary ER diagram for specifying the derivation relationships between schema versions, relationships among attributes, and the conditions for maintaining consistent views of programs. Algorithms are presented for mapping the EVER diagram into the underlying database and constructing database views for schema versions. Through the reconstruction of views after database reorganization, changes to an ER diagram can be made transparent to the application programs while all objects in the database remain accessible to the application programs.
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M3 - Conference contribution
AN - SCOPUS:84963587002
SN - 9783540587866
VL - 881 LNCS
T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
SP - 132
EP - 151
BT - Entity-Relationship Approach - ER 1994
PB - Springer Verlag
T2 - 13th International Conference on the Entity-Relationship Approach, ER 1994
Y2 - 13 December 1994 through 16 December 1994
ER -