Re: Best way to store case-insensitive data?

On Thu, 10 Jun 2010 13:50:23 -0700, Mike Christensen wrote:
> I have a column called "email" that users login with, thus I need to
> be able to lookup email very quickly.  The problem is, emails are
> case-insensitive.  I want foo@bar.com to be able to login with
> FOO@Bar.com as well.  There's two ways of doing this, that I can see:

NB: technically the local part in an email address can be case sensitive.
As RFC 5321 says:
   The local-part of a mailbox MUST BE treated as case sensitive.
   Therefore, SMTP implementations MUST take care to preserve the case
   of mailbox local-parts.  In particular, for some hosts, the user
   "smith" is different from the user "Smith".  However, exploiting the
   case sensitivity of mailbox local-parts impedes interoperability and
   is discouraged.  Mailbox domains follow normal DNS rules and are
   hence not case sensitive.

In practice I've yet to see a system having both smith and Smith
and them being different, but still it is theoretically posible.

-- 
Michał Politowski
Talking has been known to lead to communication if practiced carelessly.