I think you will find this extremely helpful. At least I hope so. Breaks down the different tables in the database and tells exactly what most are for.
http://www.eqemulator.net/wiki/wikka...DatabaseSchema
Also a good item editor would be very helpful unless you like to do it in sql directly, which is much much harder. This is my favorite one, made by GeorgeS. he also has a ton more very useful tools on his website.
http://eqemulator.net/forums/showthread.php?t=21442
Good luck!