Python psycopg2 not inserting into postgresql table

If don't want to have to commit each entry to the database, you can add the following line:

conn.autocommit = True

So your resulting code would be:

import psycopg2

try:
    conn = psycopg2.connect("dbname='djangostack' user='bitnami' host='localhost' password='password'")
    conn.autocommit = True
except:
    print "Cannot connect to db"

cur = conn.cursor()

try:
    cur.execute("""insert into cnet values ('r', 's', 'e', 'c', 'w', 's', 'i', 'd', 't')""")
except:
    print "Cannot insert"

Turns out I needed conn.commit() at the end

psycopg2 is Python DB API-compliant, so the auto-commit feature is off by default. You need to call conn.commit to commit any pending transaction to the database. As connections (and cursors) are context managers, you can simply use the with statement to automatically commit/rollback a transaction on leaving the context:

with conn, conn.cursor() as cur:  # start a transaction and create a cursor
    cur.execute(sql)

From the docs:

When a connection exits the with block, if no exception has been raised by the block, the transaction is committed. In case of exception the transaction is rolled back.

When a cursor exits the with block it is closed, releasing any resource eventually associated with it. The state of the transaction is not affected.