User defined query-able fields

[Laurent Pouillet]

On Sat, 12 Apr 2008, Mark Kretschmann wrote:
> On 4/11/08, Laurent Pouillet <laurent.pouillet at laposte.net> wrote:
>>  I have a question about the development of a feature.
>>  ...
>>  My questions are :
>>  1/ can Amarok be configured to use additional user-defined fields ? (for
>>  storing into and for reading from the SQL database)
>>  ...
>
> Amarok has a "Labels" feature; these are custom tags which are stored
> in Amarok's database. Sound like that might be what you're looking
> for.

Hello Mark, thanks for the answer ;
I have had a a look at the "Labels" field. I have seen that I creates a 
tuple in the table "labels".

But how can I change the value of a "foo" tag, specifically for a track ?
It does not appear in the "Tags" tab and in the columns of the main 
window.
Does Amarok manages to write in ogg files additional tags like [1] or [2] 
? or in mp3 files like ?
Can I write queries on "foo" in the "Edit Filter" window ?
More generally, is there a documentation about the "Labels" functionnality 
?

Thanks,

Laurent

[1] : http://xiph.org/vorbis/doc/v-comment.html
[2] : http://reactor-core.org/ogg-tagging.html