I think the best way to learn real-world data modeling, once you have the basics down,
is by reading well-regarded data models. To get the basics down (I assume you're new to SQL too), I suggest Joe Celko's "SQL for Smarties 2ed". It's clear, concise, readable, with plenty of DM info. In short, it's the best SQL book I've seen.
Most "DM+SQL" books are just not worth picking up off the shelf...
