[Xapian-discuss] Z's and other prefixes

dmorris dmorris at sirca.org.au
Fri Jun 15 02:32:11 BST 2007


Hmmm... I think that I am now more and less confused at the same time.

The prefix things and all those things makes sense. But what I now don't 
understand is the difference between "term" and "value".

Can you point me out to where would be a good place that explains the 
differences?

Cheers.



Olly Betts wrote:
> On Fri, Jun 15, 2007 at 01:10:16AM +0000, David wrote:
>   
>> Does anything else use prefixes? I haven't played around with the DateRange
>> things, but do they use specific prefixes?
>>     
>
> The DateValueRangeProcessor approach uses values rather than terms, so
> no term prefixes are involved.  Omega can use a term-based approach to
> date ranges, and that uses D, M, and Y, but now also offers a
> value-based approach.  I suspect that the term-based approach will be
> phased out eventually (but currently I've not benchmarked the two and
> I'd like to check that the new approach works better before removing
> the old one!)
>
> Prefixes can be used for probabilistic fields (e.g. to allow searching
> within the title of a document), and for boolean filters (e.g. to allow
> searches to be restricted to a particular document type).
>
> This documents the prefixes which are standardly used:
>
> http://svn.xapian.org/trunk/xapian-applications/omega/docs/termprefixes.txt?view=markup
>
> Cheers,
>     Olly
>
>   



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