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I am looking for an "elegant" solution to write, from a python script, a layer from qgis and into a new table of a PostGIS database. I thougth that this might be solved by QgsWriteVectorLayer, but I could not find any hint that this is supported. I only found the solution that this can be done e.g. with Qtsql, but then one has to:

  1. analyse the layer (field names, field datatypes, srid, ... )
  2. create the table and
  3. fill the table with date.

Question: Does pygis offers a "simple" solution to write a complete layer directly into a new PostGIS table?

  • I would use ogr2ogr: ogr2ogr -f PostgreSQL PG:dbname=mydb myshape.shp. – Jakob Jul 30 '14 at 8:12
  • this solution does not work because the layer is not a shape file but a memory layer in qgis. Exporting the memory layer to shapefile does not work because e.g. string length for fieldnames is limited in shapefiles. additionally, i do not have access to ogr2ogr in that particular environment. – gallay Jul 30 '14 at 16:47
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In order to write to the database QgsVectorLayerImport.importLayer() function have to be used.

uri = "dbname='test' host=localhost port=5432 user='user' password='password' key=gid type=POINT table=\"public\".\"test\" (geom) sql="
crs_id = 4326
crs = QgsCoordinateReferenceSystem(crs_id, QgsCoordinateReferenceSystem.EpsgCrsId)
# layer - QGIS vector layer
error = QgsVectorLayerImport.importLayer(layer, uri, "postgres", crs, False, False)
if error[0] != 0:
    iface.messageBar().pushMessage(u'Error', error[1], QgsMessageBar.CRITICAL, 5)
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You can import your shapefile to a postgis database with this python command :

import os
#Import shapefile to postgis DB
os.system("shp2pgsql -s SRID -c -D -I /path/shape.shp tablename | psql -d dbname -h localhost -U username")

(Just change : SRID (ex 4326), tablename (give any name), path, dbname and username).

  • 1
    this solution does not work because the layer is not a shape file but a memory layer in qgi (see my comment above) – gallay Jul 30 '14 at 16:48

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