Problems updating a MySQL table using Python MySQLdb

Question

I am trying to UPDATE a MySQL table using the Python MySQLdb module. Although the query seems pretty simple, it just won't update the information. Here is my code:

for username,info in users.iteritems():
  if info[0] > 0 and info[1] > 0:
    month = 8
    year = 2010
    cursor.execute("""
        UPDATE users_disk
        SET
            bytes = %s,
            quota_in_mb = %s
        WHERE
            username = %s AND
            month = %s AND
            year = %s
        """, (info[0], info[1], username, month, year))
    print "Username: %s; Rowcount: %d" % (username, cursor.rowcount)

The result is as follows:

Username: niu666; Rowcount: 0
Username: antuan; Rowcount: 0
Username: tuyo; Rowcount: 0
Username: angela; Rowcount: 0
Username: felipe; Rowcount: 0
Username: Meni; Rowcount: 0
Username: tronco; Rowcount: 0
Username: queque; Rowcount: 0
Username: cerel; Rowcount: 0

This means that none of the lines has been updated! The table has the following contents:

mysql> select * from users_disk;
+----+----------+-------+------+---------+-------------+
| id | username | month | year | bytes   | quota_in_mb |
+----+----------+-------+------+---------+-------------+
|  1 | niu666   |     8 | 2010 |   28672 |     1024000 | 
|  2 | antuan   |     8 | 2010 |   77824 |     4608000 | 
|  3 | tuyo     |     8 | 2010 |   28672 |     1024000 | 
|  4 | angela   |     8 | 2010 |   45056 |     2048000 | 
|  5 | felipe   |     8 | 2010 |   53248 |      307200 | 
|  6 | Meni     |     8 | 2010 |   86016 |     4096000 | 
|  7 | tronco   |     8 | 2010 | 3067904 |     1024000 | 
|  8 | queque   |     8 | 2010 |   61440 |     4608000 | 
|  9 | cerel    |     8 | 2010 |  110592 |     5632000 | 
+----+----------+-------+------+---------+-------------+
9 rows in set (0.00 sec)

And users is a dictionary with the following contents:

{'niu666': (28672, 1024000), 'tutk': (-1, -1), 'antuan': (77824, 4608000), 'tolin': (-1, -1), 'tuyo': (28672, 1024000), 'angela': (45056, 2048000), 'felipe': (53248, 307200), 'Meni': (86016, 4096000), 'tronco': (3067904, 1024000), 'queque': (61440, 4608000), 'cerel': (110592, 5632000), 'carok': (-1, -1), 'niu': (-1, -1)}

I think the problem may be with the username, because if I delete it, it will work. But of course I need to use it ...

Any pointers / recommendations would be highly appreciated.

Thank you very much,

Unai Rodriguez

-------------------------- Update -------------------- --- -

Guys, I use the following "ugly" workaround ... which works:

for username,info in users.iteritems():
    if info[0] > 0 and info[1] > 0:
        # The user has positive values, its valid!
        cursor.execute("DELETE FROM " + dbtable + " WHERE username = %s AND month = %s AND year = %s", \
            (username, month, year))
        cursor.execute("INSERT INTO " + dbtable + " (id, username, month, year, bytes, quota_in_mb) VALUES (NULL, %s, %s, %s, %s, %s)", \
                                            (username, month, year, info[0], info[1]))

, , UPDATE ( ). script. .

Answer 1

COMMIT :

cursor.execute("UPDATE animals SET species=%s WHERE name=%s",('TEST', 'Rollo'))

cursor.connection.commit();

Answer 2

, :

cursor.execute( <SQL_HERE> ) connection.commit().

A :

import MySQLbd
from contextlib import closing

connection = MySQLdb.connect( host="localhost",
                              user="root",
                              passwd="root",
                              db="tableName")

with closing( connection.cursor() ) as cursor:
    try:
        cursor.execute( "SQL UPDATE CODE" )
        connection.commit()
    except:
        connection.rollback()

Answer 3

, username username ? ( ), SQL , .

(id) year month, username?

Answer 4

I realized that for some reason python is not reading% s. So to use? instead of% S in your SQL code.

And finally, it worked for me.

  cur.execute ("update tablename set columnName = (?) where ID = (?) ",("test4","4"))