[Qgis-developer] Get name FID of vector Layer

[Luiz Motta]

Devs,


I need get the name field of Feature Index of vector file.

For Shapefile provider, i can use the string "FID".

But, the database provider, example Postgis or Spatialite, i need find
the name field of Primary key use for FID.

I don't find the methods in classes QgsVectorLayer and QgsDataprovider

In OGR i have the method "GetFIDColumn" (i don't test).

The idea is add in canvas the layer with FID's selected from layer.

The example of script to use in python console QGIS:

from qgis import core, gui

lyr = qgis.utils.iface.mapCanvas().currentLayer()
addLyr = core.QgsVectorLayer(lyr.source(), "test_subset", lyr.providerType())
addLyr.setSubsetString("FID IN (0,1,2)")
core.QgsMapLayerRegistry.instance().addMapLayer(addLyr)

The script run in shapefile, but, i need find the name of "Key"  in
layer from database.

Regards,
Luiz Motta