For a number of reasons, including not being able to express certain
queries into Xapian's QueryParser class (see previous post on
QueryParser bug), and the need to have users configure queries without
writing Python code, I have hacked up a quick query language for Xapian
that can best be described as "SQL-like" called xaql. It requires the
pyparsing module by Paul McGuire.
Xaql lets you specify query terms, both text and boolean that define a
Xapian query, selection variables that define which document values you
want to retrieve from the database, the values you want the results
sorted by, whether ascending or descending, a match limit, and an offset
from the match start (just like SQL). For example, we have a Xapian
database here with about 600K records with various boolean terms
indexed. Here is a xaql query and results off of that database:
$ python Xapclient.py "select xtitle, xlastposted where xstatus
in(published, reposted, expired) and xcountryid=4 and
xsubcatego\ryid=41 and xsalestype IN(individual, professional) order by
xlastposted limit 10"
Returned 10 values in 532.392024994 msec
xlastposted xtitle
1128321436 vendesi
1128325944 BUONA OCCASIONE!!!!
1128326272 Vendo PUNTO 1.7 TD ELX
1128327372 AFFARE- offro auto accessoriatissima in ottime
condizioni
1128327811 vendesi
1128328366 ferrari 348
1128331517 SAAB 900 T 2000 CABRIO - COLORE NERO - FULL OPTIONAL
1128333392 lancia dedra 2000 gas
1128335062 Toyota Corolla 1.3 SW 16V ottimo stato tutti
tagliandi Toyota
1128335073 Vendo una bellisima Smart pulse cdi nera
The xaql parser turns the above into the Xapian query:
'Xapian::Query(((XSTATUSpublished OR XSTATUSreposted OR XSTATUSexpired)
AND XCOUNTRYID4 AND XSUBCATEGORYID41 AND (XSALESTYPEindividual OR
XSALESTYPEprofessional)))'
Xaql strongly supports boolean querying (this is where
xapian.QueryParser is weakest) but also supports positional term
searching using "quoted" syntax. Here is the same search as above, but
with the text search for 'toyota':
$ python Xapclient.py "select xtitle, xlastposted where xstatus
in(published, reposted, expired) and xcountryid=4 and
xsubcatego\ryid=41 and xsalestype IN(individual, professional) and
'toyota' order by xlastposted limit 10"
Returned 10 values in 117.490053177 msec
xlastposted xtitle
1128335062 Toyota Corolla 1.3 SW 16V ottimo stato tutti
tagliandi Toyota
1128350630 vendo toyota land cruiser
1128451520 ToYota MR2
1128835801 TOYOTA Celica GTfour turbo 4wd 246cv
1129113767 vendo 4 cerchi in lega x toyota celica
1129114176 vendo sedili in pelle x toyota celica
1129283406 VENDO TOYOTA 4 RUNNER
1129538031 VENDO TOYOTA HI-LUX SR5 5 PORTE OTTOBRE 2002
1129616773 vendo Toyota Rav4 sol 5p anno 2004
1129786202 vendo toyota lj70vx preparato
I plan to keep maintaining xaql for our own purposes. If anyone is
interested in the code or have any suggestions for xaql, please let me
know.
Thanks!
-Michel