One of the most highly recommended books on data modeling is Data Modeling Essentials by Graeme Simsion (The Coriolis Group, 1996). For a quick online introduction to data modeling techniques, connect to the Applied Information Science site at www.aisintl.com/case/method.html. Another online article, "Building a Logical Data Model" at www.dbmsmag.com/9506d16.html from DBMS Online, by George Tillmann, provides a basic definition of data modeling, discusses the various elements of a data model (for example, objects, entities, relationships, and attributes), and describes how they relate to each other. The article is based on his book A Practical Guide to Logical Data Modeling (McGraw-Hill, 1993) and uses the entity-relationship approach to data modeling. The Canadian Ministry of Forests at www.for.gov.bc.ca/isb/datadmin/s7_mdl12.htm provides one of the best online sites for data modeling. By searching the Web for "data modeling," you can find other excellent data modeling sites, such as the one hosted by CERN at www.cern.ch/Adamo/guide/Chapter-2.html. Data modeling software such as Embarcadero Technologies' ER/Studio (www.embarcadero.com) helps database designers build easy-to-manipulate graphical data models, then turn them into production databases.