[Xapian-discuss] Z's and other prefixes

[Olly Betts]

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