Database schema evolution using EVER diagrams

We present an approach to schema evolution through changes to the ER diagram representing the schema of a database. In order to facilitate changes to the ER schema 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. In this paper, we demonstrate the mapping of the EVER diagram into an underlying database and the construction of 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. The EVER system can serve as a front-end for object-oriented databases.

[1]  Ramez Elmasri,et al.  Fundamentals of database systems (2nd ed.) , 1994 .

[2]  Stanley B. Zdonik,et al.  Object-Oriented Type Evolution. , 1987 .

[3]  T. J. Teorey,et al.  A logical design methodology for relational databases using the extended entity-relationship model , 1986, CSUR.

[4]  Hannu Kangassalo.  CONCEPT D: a graphical language for conceptual modelling and data base use , 1988, [Proceedings] 1988 IEEE Workshop on Visual Languages.

[5]  Stanley B. Zdonik,et al.  Type Evolution in an Object-Oriented Database , 1987, Research Foundations in Object-Oriented and Semantic Database Systems.

[6]  Shamkant B. Navathe,et al.  OOER: Toward Making the E-R Approach Object-Oriented , 1988, ER.

[7]  Panos K. Chrysanthis,et al.  Database Schema Evolution through the Specification and Maintenance of Changes on Entities and Relationships , 1994, ER.

[8]  Roberto Zicari,et al.  A framework for schema updates in an object-oriented database system , 1991, [1991] Proceedings. Seventh International Conference on Data Engineering.

[9]  Christer Hulten,et al.  Making type changes transparent , 1984 .

[10]  Peter P. Chen.  The entity-relationship model: toward a unified view of data , 1975, VLDB '75.

[11]  Ramez Elmasri,et al.  Fundamentals of Database Systems, 2nd Edition , 1994 .

[12]  Svein Erik Bratsberg.  Unified Class Evolution by Object-Oriented Views , 1992, ER.

[13]  Jay Banerjee,et al.  Semantics and implementation of schema evolution in object-oriented databases , 1987, SIGMOD '87.

[14]  Peter P. Chen.  ER vs. OO , 1992, ER.

[15]  Salvatore T. March,et al.  Proceedings of the Sixth International Conference on Entity-Relationship Approach , 1987 .

[16]  Elisa Bertino,et al.  A View Mechanism for Object-Oriented Databases , 1992, EDBT.