如何将字段添加到qgis中加载的postgis层

Question

I have loaded the layer from Postgis in qgis and i am adding the fields to the layer using the follo code snippet:

canvas = qgis.utils.iface.mapCanvas()
aLayer = canvas.currentLayer()
field_name = "test"

aLayer.startEditing()
if not field_name in fieldnames:
      res = aLayer.dataProvider().addAttributes([QgsField(field_name, QVariant.String)])
aLayer.updateFields()
aLayer.commitChanges()

but it is not adding the field to the layer. What i have to do if i want to add the fields to the layer.

Answer 1

you forgot to add the type name. just use QgsField(field_name, QVariant.String, 'varchar')

you might want to add length definition too.

you can have a look at the sip file