[Ex-plain] RE: Explain--

Robert Sanderson azaroth at liverpool.ac.uk
Fri Apr 5 18:03:17 CEST 2002

(As I've zero interest in the holdings schema, I'll write up how my 
presentation went yesterday)

> > > > What query types they support.  (Some blow up if you send
> > > > type-101.)
> > This is a good one, which I think we should include.  I know that
> > our server at least has type 0 as a way to transform SQL queries
> > into Z, but there's more useful applications for te different query
> > types.
> I guess we could support this.  But can't clients just submit a
> Type-whatever query and see whether it's accepted?  Or, Ralph, when
> you that some servers "blow up", do you mean in some completely
> catastophic way?

You could just submit a search with use 1003 to see if they support author 
searches using that logic.  

> > Argh, encapsulation, we hates it.  But at least a global 'supports
> > encapsulation' or not field somewhere would be useful.
> No, supporting encapsulation is a much bigger deal, or at least a much
> less frequently supported deal, and piggy-backing on the Search
> Request APDU.  I _think_ Ralph's right, and we should just include a
> boolean saying whether piggy-backing is supported (per-server?
> Per-DB?)

It should be somewhere in the indexInfo element. Attribute on the 
indexInfo tag?

> > > > Do they support elementSetNames.  (Horrifying as it might seem,
> > > > there are such servers.)
> > I think we can already do this, by having a record syntax tag with
> > no elementset subtags.

> Surely a <recordSyntax> with no <elementSets> merely means (as with an
> omitted "sort" attribute on an <index> element) that we're not saying
> anything one way or another?  Otherwise we need to mandate that the
> <recordSyntax>'s <elementSet>s are an exhaustive list, which doesn't
> seem realistic to me.

I think that if you're going to describe a server which has no 
attributesets, then we shouldn't have a specific way of saying 'this 
server breaks the rules'.  On the other hand, if a client encounters an 
Explain-- record with no elementsets defined in it, then IMO it should be 
free to interpret that as 'we don't have any elementsets' rather than 'my 
author was too lazy to put in the elementsets'.  


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