Hi,I suggest you to approach this question via reading a book: Modeling Our World, Second Edition: The Esri Guide to Geodatabase Concepts.http://esripress.esri.com/display/index.cfm?fuseaction=display&websiteID=178&moduleID=0If you want to take a look at the data model directly, Esri and Esri's user community have prepared quite a few geodatabase models which are available for download. Depending on how well they suit you, you might need to adjust the database structure, tables, etc., but it is definitely a good start point.http://support.esri.com/en/downloads/datamodel