#!/usr/bin/python
# -*- coding: utf-8 -*-

from psycopg2 import connect
import sys
from psycopg2.extensions import ISOLATION_LEVEL_AUTOCOMMIT

con = None
con = connect(user='postgres', password='poilk', port=5432)

dbname = "name_db"

con.set_isolation_level(ISOLATION_LEVEL_AUTOCOMMIT)
cur = con.cursor()
cur.execute('CREATE DATABASE ' + dbname)
cur.close()
con.close()

Traceback (most recent call last):
  File "C:Program Files (x86)JetBrainsPyCharm 2016.1.2helperspydevpydevd.py", line 1531, in <module>
    globals = debugger.run(setup['file'], None, None, is_module)
  File "C:Program Files (x86)JetBrainsPyCharm 2016.1.2helperspydevpydevd.py", line 938, in run
    pydev_imports.execfile(file, globals, locals)  # execute the script
  File "D:/ALEX/Proktor/From_life_to_life/Work_with_db.py", line 15, in <module>
    cur.execute('CREATE DATABASE ' + dbname)
psycopg2.ProgrammingError: ОШИБКА:  база данных "name_db" уже существует

con = connect(user='postgres', password='poilk', port=5432)

dbname = "name_db"

con.set_isolation_level(ISOLATION_LEVEL_AUTOCOMMIT)
cur = con.cursor()
try:
    cur.execute('CREATE DATABASE ' + dbname)
except psycopg2.ProgrammingError as e:
    print("Already exists")

con = connect(user='postgres', password='poilk', port=5432)
# Без указания имени БД, соеденение будет с базой postgres

dbname = "name_db"

cur = con.cursor()
cur.execute("SELECT 1 FROM pg_database WHERE datname='{dbname}'".
                                                    format(db_name=settings.DB_NAME))

print(cur.fetchone())