用于 CSV 导入的 SQLite 事务

I'm very new to python and have been working on my raspberry pi to get a script up and running to import millions of sensor data records into sqlite. I want to do this in transactions to make the process more efficient. I am trying to break the transactions down into 10k chunks as done here: Python CSV to SQLite

到目前为止我有

import csv, sqlite3, time

def chunks(data, rows=10000):
    for i in range (0, len(data), rows):
            yield data[i:i+rows]

if __name__ == "__main__":

    t = time.time()

con = sqlite3.connect('test.db')
cur = con.cursor()
cur.execute("DROP TABLE IF EXISTS sensor;")
cur.execute("CREATE TABLE sensor(key INT, reading REAL);")

filename = 'dummy.csv'
reader = csv.reader(open(filename,"r"))
divdata = chunks(reader)

for chunk in divdata:
    cur.execute('BEGIN TRANSACTION')

    for col1, col2 in chunk:
            cur.execute('INSERT INTO sensor (key, reading) VALUES (?, ?)', (col1, col2))

    con.execute('COMMIT')

我在 python 3.2.3 中遇到以下错误:

Traceback (most recent call last):
File "/home/pi/test1.py", line 20, in <module>
for chunk in divdata:
File "/home/pi/test1.py", line 4, in chunks
for i in range (0, len(data), rows):
TypeError: object of type '_csv.reader' has no len()