On Fri, 27 Aug 2004, Ray Denenberg wrote:

>>> (BTW, I find the word "default" a bit ambiguous. It seems to be
>>> implied that the CQL context set itself is "the default", see
>>> http://www.loc.gov/z3950/agency/zing/cql/context-sets.html )

> context set". The problem is that a context set includes an index. So I can
> see where this terminology generates confusion, compounded by the fact that
> the index default is per server and the context set default is global.  I
> think it would be good not to use the term "default context set", use
> instead "general context set".

So long as it's obvious that components other than indexes without a
prefix by definition are from cql.

> Then you have a server's default index, and a general context set (which
> we could describe as prescribing global default values for everything
> except the index).

This is nothing new, but bears repeating.

'CQL' is the context set which is assumed for CQL components other than
indexes.  Everything else is up to the server to decide, and it may
publish any such decisions in Explain (but it doesn't have to)  Even if it
does publish a default context set, it may still choose to use a different
one for any particular query.

When I ask for cql.serverChoice, it might look at the term and say
'that looks like a subject, I'll search there' or it might decide to
search titles or full text.  The same applies to the cql.scr relation.
(Hence cql.serverChoice, rather than cql.default, I guess)

The server cannot make such a decision for things other than indexes.  If
I ask for:  dc.title fooRelation fish, the server must respond with a
diagnostic that cql doesn't define a 'fooRelation' relation.

Also for indexes we can specify a default context set in the query.
    > "info:.../dcv1.1" title any fish
is explicitly title from dublin core.

So a query might have a default context set. A server might also have a
default context set (eg, it's saying that it will try and use it if one
isn't given) and the query language has a default context set for things
other than indexes.

Rob


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