SQL

The Nuts And Bolts of Relational Databases (an e-journal article)

Data Modeling: Finding the Perfect Fit (an article by Tim McLellan)

Oracle Documentation at FNAL

SQL Tutorial (by James Hoffman)

Oracle/SQL Tutorial (UC Davis)

SQL for Web Nerds (by Philip Greenspun)

Introduction to SQL from the book "CGI Programming on the World Wide Web"

A Minimal SQL Primer