So my index in my county table should be the state_code? I really can't think of what I would index in my States table since it just lists each state once along with a unique identifier called state_code.
So my index in my county table should be the state_code? I really can't think of what I would index in my States table since it just lists each state once along with a unique identifier called state_code.
No. I would make the index the one with the greatest selectivity, which would probably be a composite on State and County.