Create a Postgres database using python

Question

I want to create Postgres database using Python.

con = psql.connect(dbname='postgres',       user=self.user_name, host='',       password=self.password)  cur = con.cursor() cur.execute("CREATE DATABASE %s  ;" % self.db_name) 

I am getting the following error:

InternalError: CREATE DATABASE cannot run inside a transaction block 

I am using psycopg2 to connect. I don't understand what's the problem. What am I trying to do is to connect to database (Postgres):

psql -postgres -U UserName 

And then create another database:

create database test; 

This is what I usually do and I want to automate this by creating Python script.

Answer 1

Use ISOLATION_LEVEL_AUTOCOMMIT, a psycopg2 extensions:

No transaction is started when command are issued and no commit() or rollback() is required.

import psycopg2 from psycopg2 import sql from psycopg2.extensions import ISOLATION_LEVEL_AUTOCOMMIT # <-- ADD THIS LINE  con = psycopg2.connect(dbname='postgres',       user=self.user_name, host='',       password=self.password)  con.set_isolation_level(ISOLATION_LEVEL_AUTOCOMMIT) # <-- ADD THIS LINE  cur = con.cursor()  # Use the psycopg2.sql module instead of string concatenation  # in order to avoid sql injection attacs. cur.execute(sql.SQL("CREATE DATABASE {}").format(         sql.Identifier(self.db_name))     ) 

Answer 2

As shown in the other answer the connection must be in autocommit mode. Another way of setting it using psycopg2 is through the autocommit attribute:

import psycopg2 from psycopg2 import sql  con = psycopg2.connect(...) con.autocommit = True  cur = con.cursor() # sql.SQL and sql.Identifier are needed to avoid SQL injection attacks. cur.execute(sql.SQL('CREATE DATABASE {};').format(     sql.Identifier(self.db_name)))