psycopg2 not actually inserting data

I need to insert JSON data from tornado to postgres, so here's test like this:

from psycopg2 import connect

conn = connect("user='pguser' host='localhost' dbname='pgdb' password='pgpass'")
cursor = conn.cursor()

data = '[{"id":"sdf","name":"wqe","author":"vb"}]'

for row in eval(data):
  print row
  cursor.execute("""INSERT INTO books(id,name,author) VALUES('%s','%s','%s')""" % \
        (row['id'], row['name'], row['author'])
  )

>>> cursor.execute("SELECT * FROM books")
>>> cursor.fetchall()
[('sdf', 'wqe', 'vb')]
>>> 
$> psql -d pgdb -U pguser -W
Password for user pguser: 
psql (9.1.6)
Type "help" for help.

pgdb=> select * from books;
 id | name | author 
----+------+--------
(0 rows)

As you can see after doing select in python shell, there's some data, but in psql there's 0 rows! What may I be doing wrong?

Python 2.7.2+

You didn't commit the transaction.

Psycopg2 opens a transaction automatically, and you must tell it to commit in order to make the data visible to other sessions.

See the psycopg2 FAQ and the connection.commit() method.

Just had the same perplexing issue. To put options together:

as @Craig Ringer writes after cursor.execute you can run connection.commit

cursor.execute('INSERT INTO table VALUES(DEFAULT, %s)', email)
...
connection.commit()

OR after connect set autocommit

connection = connect("user='pguser' host='localhost' dbname='pgdb' password='pgpass'")
connection.autocommit = True

OR use set_session to set autocommit

connection = connect("user='pguser' host='localhost' dbname='pgdb' password='pgpass'") 
connection.set_session(autocommit=True)

All worked for me.