Well, I did some studying re Normalization. I then took some time away from it hoping it might help me get my head around it, but I'm afraid I'm still rather clueless.
I was reluctant to divulge my intentions, but what the hey.
I'm developing an anti-SPAM tool for Mods of a popular forum
Even if I leave out IPs (low ROI for higher overhead) and Comments, I'm still at a loss determining how to not have rows with unused fields (up to around a dozen of them per row). eg.
Member_1 - URL_1 - URL_2 - URL_3
Member_2 - URL_1 - NULL - NULL
Member_3 - URL_1 - URL_2 - NULL
Member_4 - URL_1 - NULL - NULL
Member_5 - URL_1 - NULL - NULL
URL_1 - Member_1 - Member_2 - Member_3
URL_2 - Member_1 - NULL - NULL
URL_3 - Member_1 - Member_2 - NULL
URL_4 - Member_1 - NULL - NULL
URL_5 - Member_1 - NULL - NULL
and Id rather not do 2 fields with comma delimiter
Member_1 - URL_1, URL_2, URL_3
Member_2 - URL_1
Member_3 - URL_1, URL_2
Member_4 - URL_1
Member_5 - URL_1
URL_1 - Member_1, Member_2, Member_3
URL_2 - Member_1
URL_3 - Member_1, Member_2
URL_4 - Member_1
URL_5 - Member_1
Am I over-thinking this or am I as clueless as I feel?