title: DB optimization and normalization
body: <p>I have several tables with geodata: <code>countries</code>, <code>regions</code>, <code>cities</code>. Also I have a table with user profiles. Is there any logic to add <code>country_id</code>, <code>region_id</code> and <code>city_id</code> to <code>profiles</code> table? If talking about normalizing - it's wrong, because <code>cities</code> table has <code>region_id</code> and <code>regions</code> table has <code>country_id</code>, but in this case we will have additional queries.</p>