Thanks I'll check that out. I'm mainly using the VRT in QGIS against Ingres database. QGIS isn't doing filtering properly for me, (even with passthrough=true) so I'm trying to discern whether it's a deficiency of our Ingres driver or if the functionality just doesn't exist yet elsewhere :)
On 2012-05-18, at 3:10 AM, Even Rouault wrote: > Le vendredi 18 mai 2012 07:12:03, Tyler Mitchell a écrit : >> I've done my best to comb through the code but can't see how to use an >> attribute filter in a (OGR) VRT definition. > > Tyler, > > You have 2 possibilities : > > 1) Probalby not what you want for your use case, but you can set a OGR VRT > and > set externally an attribute filter on the returned layer. The attribute > filter > should be applied directly on the underlying source layer if you set > <attrFilterPassThrough>TRUE</attrFilterPassThrough> in the <OGRVRTLayer> (or > if no explicit <Field> is present, or -in trunk- automatically in compatible > cases) > > 2) Or you use a <SrcSQL> definition with a WHERE clause in it. In case the > underlying datasource as a specific implementation of ExecuteSQL() , that > should be efficient (and even if it doesn't the generic OGR SQL engine should > extract the WHERE clause and pass it to the SetAttributeFilter() > implementation of the underlying layer) > > Even > >> >> Tyler_______________________________________________ >> gdal-dev mailing list >> [email protected] >> http://lists.osgeo.org/mailman/listinfo/gdal-dev Tyler Mitchell Engineering Director Actian Corporation [email protected] MOBILE 250-303-1831 SKYPE spatialguru www.actian.com
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