A data model is a representation of the information consumed and produced by a system. Data modeling involves analyzing the data objects present in a system and the relationships between them. PowerDesigner® provides conceptual, logical, and physical data models to allow you to analyze and model your system at all levels of abstraction.
Graeme Simsion, Van Nostrand Reinhold, Data Modeling Essentials, 1994, 310 pages; paperbound; ISBN 1850328773
James Martin, Prentice Hall, Information Engineering, 1990, three volumes of 178, 497, and 625 pages respectively; clothbound, ISBN 0-13-464462-X (vol. 1), 0-13-464885-4 (vol. 2), and 0-13-465501-X (vol. 3).
Joe Celko, Joe Celko's SQL for Smarties (Morgan Kaufmann Publishers, Inc., 1995), 467 pages; paperbound; ISBN 1-55860-323-9.