我想要加载一个看起来像这样的CSV文件:
Acct. No.,1-15 Days,16-30 Days,31-60 Days,61-90 Days,91-120 Days,Beyond 120 Days
2314134101,898.89,8372.16,5584.23,7744.41,9846.54,2896.25
2414134128,5457.61,7488.26,9594.02,6234.78,273.7,2356.13
2513918869,2059.59,7578.59,9395.51,7159.15,5827.48,3041.62
1687950783,4846.85,8364.22,9892.55,7213.45,8815.33,7603.4
2764856043,5250.11,9946.49,8042.03,6058.64,9194.78,8296.2
2865446086,596.22,7670.04,8564.08,3263.85,9662.46,7027.22
,4725.99,1336.24,9356.03,1572.81,4942.11,6088.94
,8248.47,956.81,8713.06,2589.14,5316.68,1543.67
,538.22,1473.91,3292.09,6843.89,2687.07,9808.05
,9885.85,2730.72,6876,8024.47,1196.87,1655.29
但是如果您注意到,有一些字段是不完整的。我认为MySQL会直接跳过第一列缺失的行。当我运行以下命令时:
LOAD DATA LOCAL INFILE 'test-long.csv' REPLACE INTO TABLE accounts
FIELDS TERMINATED BY ',' LINES TERMINATED BY '\r\n'
IGNORE 1 LINES
(cf_535, cf_580, cf_568, cf_569, cf_571, cf_572);
MySQL 的输出结果如下:
Query OK, 41898 rows affected, 20948 warnings (0.78 sec)
Records: 20949 Deleted: 20949 Skipped: 0 Warnings: 20948
行数只有20949行,但MySQL报告影响了41898行。为什么会这样?而且表中什么也没变。我也看不出生成的警告是关于什么的。我想使用LOAD DATA INFILE,因为它只需要半秒钟就能更新一行数据,对于一个包含20000多条记录的文件来说,这相当于2.77小时。
更新:修改代码将自动提交设置为“False”,并添加了db.commit()语句。
# Tell MySQLdb to turn off auto-commit
db.autocommit(False)
# Set count to 1
count = 1
while count < len(contents):
if contents[count][0] != '':
cursor.execute("""
UPDATE accounts SET cf_580 = %s, cf_568 = %s, cf_569 = %s, cf_571 = %s, cf_572 = %s
WHERE cf_535 = %s""" % (contents[count][1], contents[count][2], contents[count][3], contents[count][4], contents[count][5], contents[count][0]))
count += 1
try:
db.commit()
except:
db.rollback()