[Mapserver-users] OGR Join index
Richard Greenwood
rich at greenwoodmap.com
Fri Jun 18 13:27:08 PDT 2004
Frank Warmerdam wrote:
> Richard Greenwood wrote:
>
>> There is mention of CREATE INDEX in:
>> http://gdal.velocet.ca/projects/opengis/ogrhtml/ogr_sql.html
>> Can you shed any light on that?
>
>
>
> Richard,
>
> As far as I know that only works for MapInfo format currently.
>
> ... slow fade in of memory ...
>
> Now I remember. It does also work for shapefiles though ironically it
> creates a Mapinfo format attribute index for the shapefile's dbf. However,
> yes, the CREATE INDEX stuff should work for shapefile datasets too and
> substantially accelerate attribute queries, in particular integer key
> lookups.
>
Very interesting! So I could use MapInfo to create indexes and OGR would
use them? And if I wanted to use ORG's CREATE INDEX I would need to
write a C or Python wrapper? i.e. There is no stand alone CREATE INDEX
utility?
As always, thank you!
--
Richard Greenwood
www.greenwoodmap.com
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