Nathan Thanks for pointer, I hadn't seen that, and certainly it is a similar thing in terms of implementation (ie when the filter is applied as features are extracted).
There would still be the question of where and how the request is presented to the user (ie what sort of request is available, though of course an expression based filter is always an option), and how it is defined with the layer and persisted into the project. Also the subset has its own feature count and extents, so that may not sit will with a feature request implementation. Chris ________________________________________ From: Nathan Woodrow [[email protected]] Sent: 30 April 2013 18:55 To: Chris Crook Cc: [email protected] Subject: Re: [Qgis-developer] QgsDataProvider and supportsSubsetString Chris, Also not there is previsions to add this kind of thing to QgsFeatureRequest http://www.qgis.org/api/qgsfeaturerequest_8h_source.html - Nathan On Tue, Apr 30, 2013 at 4:33 PM, Chris Crook <[email protected]<mailto:[email protected]>> wrote: Hi All As we are looking at API tidy ups (I understand), would there be any support for providing a bit more granularity in supportsSubsetString. At the moment this is a simple boolean, and the GUI offers a SQL based subset string builder. However not all providers naturally use SQL based strings. I'm interested in adding subset capability to the delimited text provider, whichi I've done using QgsExpression as the basis for subsets. This works very well except that the GUI isn't an expression builder. I think there may be similar issues with the WFS provider. What I am proposing is something more like an enum QgsDataProvider::SubsetStringType, which could then be interrogated by the properties dialog to select the appropriate query builder dialog. Logically this would supplant the supportsSubsetString boolean which could be deprecated, replaced with virtual QgsDataProvider::SubsetStringType QgsDataProvider::subsetStringType(){ return NoSubsetString; } Other types could be SqlSubsetString, ExpressionSubsetString, ...? Thoughts anyone? Thanks Chris This message contains information, which is confidential and may be subject to legal privilege. If you are not the intended recipient, you must not peruse, use, disseminate, distribute or copy this message. If you have received this message in error, please notify us immediately (Phone 0800 665 463 or [email protected]<mailto:[email protected]>) and destroy the original message. LINZ accepts no responsibility for changes to this email, or for any attachments, after its transmission from LINZ. Thank You. _______________________________________________ Qgis-developer mailing list [email protected]<mailto:[email protected]> http://lists.osgeo.org/mailman/listinfo/qgis-developer _______________________________________________ Qgis-developer mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/qgis-developer
