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Merge pull request #7064 from anitagraser/patch-1

[FEATURE] Create PostGISExecuteAndLoadSQL.py
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m-kuhn committed Jun 25, 2018
2 parents fd8344b + 4a48f50 commit 7acfe037c449e38692fb30c729afc54c4edc2c42
@@ -356,6 +356,9 @@ qgis:spatialiteexecutesql: >
qgis:postgisexecutesql: >
This algorithm performs a SQL database query on a PostGIS database connected to QGIS.

qgis:postgisexecuteandloadsql: >
This algorithm performs a SQL database query on a PostGIS database connected to QGIS and loads the query results as a new layer.

qgis:randomextract: >
This algorithm takes a vector layer and generates a new one that contains only a subset of the features in the input layer.

@@ -0,0 +1,117 @@
# -*- coding: utf-8 -*-

"""
***************************************************************************
PostGISExecuteAndLoadSQL.py
---------------------
Date : May 2018
Copyright : (C) 2018 by Anita Graser
Email : anitagraser at gmx dot at
---------------------
based on PostGISExecuteSQL.py by Victor Olaya and Carterix Geomatics
***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************
"""

__author__ = 'Anita Graser'
__date__ = 'May 2018'
__copyright__ = '(C) 2018, Anita Graser'

# This will get replaced with a git SHA1 when you do a git archive

__revision__ = '$Format:%H$'

from qgis.core import (Qgis,
QgsProcessingException,
QgsProcessingParameterString,
QgsApplication,
QgsVectorLayer,
QgsProject,
QgsProcessing,
QgsProcessingException,
QgsProcessingOutputVectorLayer,
QgsProcessingContext,
QgsProcessingFeedback)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from processing.tools import postgis


class PostGISExecuteAndLoadSQL(QgisAlgorithm):

DATABASE = 'DATABASE'
SQL = 'SQL'
OUTPUT = 'OUTPUT'
ID_FIELD = 'ID_FIELD'
GEOMETRY_FIELD = 'GEOMETRY_FIELD'

def group(self):
return self.tr('Database')

def groupId(self):
return 'database'

def __init__(self):
super().__init__()

def initAlgorithm(self, config=None):
db_param = QgsProcessingParameterString(
self.DATABASE,
self.tr('Database (connection name)'))
db_param.setMetadata({
'widget_wrapper': {
'class': 'processing.gui.wrappers_postgis.ConnectionWidgetWrapper'}})
self.addParameter(db_param)
self.addParameter(QgsProcessingParameterString(
self.SQL,
self.tr('SQL query'),
multiLine=True))
self.addParameter(QgsProcessingParameterString(
self.ID_FIELD,
self.tr('Unique ID field name'),
defaultValue='id'))
self.addParameter(QgsProcessingParameterString(
self.GEOMETRY_FIELD,
self.tr('Geometry field name'),
defaultValue='geom',
optional=True))
self.addOutput(QgsProcessingOutputVectorLayer(
self.OUTPUT,
self.tr("Output layer"),
QgsProcessing.TypeVectorAnyGeometry))

def name(self):
return 'postgisexecuteandloadsql'

def displayName(self):
return self.tr('PostGIS execute and load SQL')

def processAlgorithm(self, parameters, context, feedback):
connection = self.parameterAsString(parameters, self.DATABASE, context)
id_field = self.parameterAsString(parameters, self.ID_FIELD, context)
geom_field = self.parameterAsString(
parameters, self.GEOMETRY_FIELD, context)
uri = postgis.uri_from_name(connection)
sql = self.parameterAsString(parameters, self.SQL, context)
sql = sql.replace('\n', ' ')
uri.setDataSource("", "(" + sql + ")", geom_field, "", id_field)

vlayer = QgsVectorLayer(uri.uri(), "layername", "postgres")

if not vlayer.isValid():
raise QgsProcessingException(self.tr("""This layer is invalid!
Please check the PostGIS log for error messages."""))

context.temporaryLayerStore().addMapLayer(vlayer)
context.addLayerToLoadOnCompletion(
vlayer.id(),
QgsProcessingContext.LayerDetails('SQL layer',
context.project(),
self.OUTPUT))

return {self.OUTPUT: vlayer.id()}
@@ -101,6 +101,7 @@
from .Polygonize import Polygonize
from .PolygonsToLines import PolygonsToLines
from .PostGISExecuteSQL import PostGISExecuteSQL
from .PostGISExecuteAndLoadSQL import PostGISExecuteAndLoadSQL
from .RandomExtract import RandomExtract
from .RandomExtractWithinSubsets import RandomExtractWithinSubsets
from .RandomPointsAlongLines import RandomPointsAlongLines
@@ -216,6 +217,7 @@ def getAlgs(self):
Polygonize(),
PolygonsToLines(),
PostGISExecuteSQL(),
PostGISExecuteAndLoadSQL(),
RandomExtract(),
RandomExtractWithinSubsets(),
RandomPointsAlongLines(),

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