cakephp/docs — comment on commit 6df0f512e13a3fc5af62c328a687dc697f9c89e9
File: en/development/configuration.rst line 80
By ADmad:

"For MySQL to connect via socket specify the `unix_socket` parameter instead of `host` and `port`"
This comment in app/Config/database.php.default is pretty clear imo.