Up to now in my programming career (two years) I have not had much database experience, but the company where I now work uses databases extensively for their product, and I
Learn database fundamentals and t-sql first before even considering using LINQ. If you don't understand how joins work and how databases should be structured you cannot effectively query using any tool.
Here are some links to help: http://www.tek-tips.com/faqs.cfm?fid=4785 http://www.deeptraining.com/litwin/dbdesign/FundamentalsOfRelationalDatabaseDesign.aspx