Database Case Insensitive Index?

Question

I have a query where I am searching against a string:

SELECT county FROM city WHERE UPPER(name) = \'SAN FRANCISCO\';

Now, this works fine,

Answer 1

You could add an indexed column holding a numerical hash key of the city name. (With duplicates allowed).

Then you could do a multi-clause where :

hash = [compute hash key for 'SAN FRANCISCO']

SELECT county 
FROM city 
WHERE cityHash = hash 
  AND UPPER(name) = 'SAN FRANCISCO' ;

Alternatively, go through your db manual and look at the options for creating table indexes. There might be something helpful.