python - 使用 Python 的 MySQLdb 更新 MySQL 表的问题

Question

我正在尝试使用 Python 的 MySQLdb 模块更新 MySQL 表。尽管查询看起来相当简单，但它不会更新信息。这是我的代码:

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)

输出看起来像这样:

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

这意味着没有任何行被更新!该表具有以下内容:

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)

users是一个字典，内容如下:

{'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)}

我认为这个问题可能与用户名有关，因为如果我删除它，更新就会生效。但是我当然需要使用它...

我们将不胜感激任何指点/建议。

非常感谢，

乌奈·罗德里格斯

------------------------更新-------------------- -----

伙计们，我正在使用以下“丑陋”的解决方法……有效:

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]))

我仍然很想知道 UPDATE(第一次实现)出了什么问题。我暂时保留这样的脚本。非常感谢。

Answer 1

您是否在更新后尝试使用 COMMIT 命令，如下所示？

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

cursor.connection.commit();