[gdal-dev] Motion: Adopt RFC 29: OGR Set Ignored Fields

[Frank Warmerdam]

On Fri, Aug 6, 2010 at 10:48 AM, Tamas Szekeres <szekerest at gmail.com> wrote:
> +1
>
> I assume that this feature will be utilized in the OGR sql query processor
> and not directly in the ogr2ogr application.

Tamas,

ogr2ogr has a -select switch to identify desired fields
to be copied to the output.  I imagine ogr2ogr could
benefit from ignoring all the undesired attributes using
this new api.

Currently there is no logic in the OGR SQL engine to
ignore fields not needed in the result but I can see that
adding this would be desirable.  It would require some
work to walk all the expression trees (for the WHERE
and each of the column expressions) to identify the
fields that are used in the primary and joined tables.  I
would potentially be willing to implement this optimization.

Re: the TestCapability(), I'd like to see this added too.
I think this could be done without restarting the RFC
process.

Best regards,
-- 
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