[Dovecot] MySQL table for use with dict et quota

In your "http://wiki.dovecot.org/Quota/Dict" documentation, the table to create is :

create table quota ( path varchar(255) not null primary key, username varchar(255) not null, current integer );

"path" field is the primary key. But when i see the SELECT queries, "path" is always used ('quota/storage') and username too. I don't understand... If "path" is the primary key, it must be unique in quota table ?

Perhaps the table would be like this :

create table quota ( path varchar(255) not null, username varchar(255) not null, current integer, primary key (path, username) );

No ?

I start to have a headache... :D 2 days with dovecot quota, and no fully working results :'(

Please, help me :)

Mikaël