There are numerous posts that are floating around the blogosphere and forums on getting MySQL working on Leopard (as in “cannot connect through /tmp/mysql). Some of them seem to be a bit over a top, and the solution I found (which may exist elsewhere) is quick and easy.

Open /etc/my.cnf as root:

    $ sudo nano -w /etc/my.cnf

Replace all occurrences of

    socket = /var/mysql/mysql.sock

 socket = /tmp/mysql.sock

Restart MySQL using either the preference pane or with the command line, and you should be away.

I think your mileage may vary, but for me, CocoaMySQL nor Ruby could connect to the MySQL daemon out of the box.