Re: native xml processing vs what Postgres and Oracle offer

paul c wrote:

>Bob Badour wrote:
>...
>> A much bigger problem with google groups is the inability to filter the
>> self-aggrandizing ignorants.
>
>Filtering looks like a functional requirement to me, I guess it would
>amount to restriction in relational terms. With the hierarchy if person
> B answers (person) A and C filters B, then it gets murky if person D
>responds to B. Maybe there are now two disconnected trees, maybe there
>is one, who knows?

Filtering commonly happens on threads, i.e. the transitive closure of the is-reply-to relationship between messages. E.g. in my newsreader I can just enter

  /Bob Badour/f:,

to omit all messages from Bob Badour with all direct or indirect replies. So the modelling language and/or query language must be capable of expressing this; e.g. one solution would be to explicitly add the is-eventually-reply-to relation with constraints to express its being the closure of is-reply-to.

-- 
Reinier