Include an array of 20k zip codes or call MySQL : <p>I have a list of about 20,000 zip codes that I need to check against. Should I store them in an PHP file as an array? How much memory would that occupy?</p>

<p>Or should I call MySQL every time to check against its database table to see if it exists? Which way is faster? I assume the first option should be faster? The connection to database alone may slow down the database call option quite significantly? I'm just a bit concerned about that memory problem if I do it by including PHP file on every call.</p>
