使用QGIS为Python插件调用QgsDataSourceUri

Question

TLDR : using QGIS, I'm trying to develop a python plugin to update a database. Unfortunately I get immediatly an error : Traceback (most recent call last): File "", line 1, in NameError: name 'QgsDataSourceUri' is not defined

More detailed:

I work on QGIS2.18 to develop a plugin to update some data located on a postgres database. for this, I want to use this kind of code:

from qgis.core import *
from PyQt4.QtCore import *
from PyQt4.QtCore import QSettings
from PyQt4.QtCore import QSettings
from qgis.core import QgsVectorLayer, QgsDataSourceURI

uri = QgsDataSourceUri()

# set host name, port, database name, username and password
uri.setConnection(hote_IP, "5432", base_de_donnee, utilisateur,     mot_de_passe)
# set database schema, table name, geometry column and optionally
# subset (WHERE clause)
#uri.setDataSource("public", "roads", "the_geom", "cityid = 2643")

uri.setDataSource("", sql, "geom", "", "gid")
vlayer = QgsVectorLayer(uri.uri(), zapm, "postgres")
QgsMapLayerRegistry.instance().addMapLayer(vlayer)

(I got the code from the net, I'll adapt it later on)

My problem : when I try to run this code on the Python console of QGIS, I immediatly get the error

Traceback (most recent call last): File "", line 1, in NameError: name 'QgsDataSourceUri' is not defined

even when I only run the import and the line uri = QgsDataSourceUri() , I get the same error message.

I have not been able to find out how to correct this issue.

problem of installation of QGIS? of python? bad imports?

Config: qgis 2.18.20 python 3.6.5

If anyone has an idea on how to solve this, I would be really glad.

Thanks, Erwann

Answer 1

You simply are using the wrong class name. It should be uri = QgsDataSourceURI() instead of uri = QgsDataSourceUri() because you've imported QgsDataSourceURI and not QgsDataSourceUri

QGIS and QT Python classes are case-sensitive. You can confirm the exact syntax looking at QGIS 2.18 related API .