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(at)bar(dot)com to be able to login with
> FOO(at)Bar(dot)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.