QGIS » QGIS Application

#!/usr/bin/env python

# -*- coding: utf-8 -*-

# ----- define Interface -----

##PostgreSQL/PostGIS administration (QGIS 2.x)=group

##Create sequence as default value=name

##Input_layer=vector

##Input_column=field Input_layer

from PyQt4.QtCore import *

from PyQt4.QtGui import *

from PyQt4 import *

from qgis.core import *

from qgis.gui import *

from qgis.utils import *

import psycopg2

import re

# ----- get input parameters from GUI -----

inlayer = processing.getObject(Input_layer)

inlayer_dp = inlayer.dataProvider().dataSourceUri()

# get database parameters ('Input layer a')

db_name = QgsDataSourceURI(inlayer_dp).database()

db_host = QgsDataSourceURI(inlayer_dp).host()

db_user = QgsDataSourceURI(inlayer_dp).username()

db_password = QgsDataSourceURI(inlayer_dp).password()

# get layer a parameters

inlayer_schema = QgsDataSourceURI(inlayer_dp).schema()

inlayer_table = QgsDataSourceURI(inlayer_dp).table()

inlayer_column = Input_column

# ----- check input layers -----

# ...

# ----- connect to database -----

conn = psycopg2.connect( "dbname={0} host={1} user={2} password={3}".format( db_name, db_host, db_user, db_password ) )

# create and run query

with conn.cursor() as curs:

    sql = """CREATE SEQUENCE "{0}"."{1}_{2}_seq" OWNED BY "{0}"."{1}"."{2}";

    SELECT SETVAL('"{0}"."{1}_{2}_seq"', (SELECT MAX("{2}") FROM "{0}"."{1}"));

    ALTER TABLE "{0}"."{1}"

    ALTER COLUMN "{2}" SET DEFAULT nextval('"{0}"."{1}_{2}_seq"'::regclass);

    """.format ( inlayer_schema, inlayer_table, inlayer_column )

    curs.execute(sql)

    # commit changes if everything went OK

    conn.commit()