disk I/O error with SQLite3 in Python 3 when writing to a database

问题

i am a student just starting out with python, and i was tasked with creating a relational database management system. I think i came pretty far, but i seem to have hit a wall. This is my code:

import csv
import sqlite3

conn = sqlite3.connect('unfccc.db')
c = conn.cursor()

c.execute('''CREATE TABLE unfccc (
        Country TEXT, 
        CodeCountryFormat TEXT, 
        NamePollutant TEXT, 
        NameYearSector TEXT, 
        NameParent TEXT, 
        Sector TEXT, 
        CodeSector TEXT, 
        CNUEDSPD TEXT
        )''')

def insert_row(Country, CodeCountryFormat, NamePollutant, NameYearSector, NameParent, Sector, CodeSector, CNUEDSPD):
    c.execute("INSERT INTO unfccc VALUES (?, ?, ?, ?, ?, ?, ?, ?)", (Country, CodeCountryFormat, NamePollutant, NameYearSector, NameParent, Sector, CodeSector, CNUEDSPD))
    conn.commit()

with open('UNFCCC_v20.csv') as csvfile:
    readCSV = csv.reader(csvfile, delimiter='\t')

    counter = 0

    for row in readCSV:
        insert_row(row[0], row[1], row[2], row[3], row[4], row[5], row[6], row[7])
        counter = counter+1
        print('%d down, more to go' % counter)
conn.close()

when i run it with line 4 directing the input towards :memory: it works perfectly and i have myself what i think is a relational database.

However, when i try to run the code like this, writing the data to a db file, i get this error:

 File "<ipython-input-13-4c50216842bc>", line 19, in insert_row
    c.execute("INSERT INTO unfccc VALUES (?, ?, ?, ?, ?, ?, ?, ?)", (Country, CodeCountryFormat, NamePollutant, NameYearSector, NameParent, Sector, CodeSector, CNUEDSPD))

OperationalError: disk I/O error

I've searched stackoverflow, and i've used google, but i don't think any of the cases i found match up to what i'm trying to do here (or i don't have the knowledge to figure out whats going on). One other thing i noticed about my code is that it inputs the data into memory super fast, but when i write to a db file it is really slow, it shouldn't be a hardware limit as i am using an SSD. Any help will be greatly appreciated!

回答1:

Setting Backup/Sync to pause on the system tray icon while working with a project stored on Google Drive will prevent disk i/o errors.

This is because when the file is written to or changed, backup & sync attempts to upload the new version to your Google Drive, while it is doing this; the file becomes a 'Read-Only' file.

While sync is paused your Google Drive folder acts more like a normal directory.

(click -> settings -> pause/resume)

回答2:

Another cause for this problem is if the journal file is not writable, but the SQLite data file is writable. If the SQLite data file isn't writable, it will tell you you're trying to write to a read-only database. But if the database file is writable, but the journal file (filename same as the SQLite data file, but ending in -journal) isn't writable, it will give you an I/O error instead.

回答3:

The answer was simple, i was working from my Google Drive directory on my personal computer, i was offline at the time of the error and the Backup and Sync program was not running therefore it took me a while to realize that i still don't have full permissions over the folder.

Moving my script and necessary files to a folder in my Documents fixed the error. Thanks for the help Marco and Josh!

来源：https://stackoverflow.com/questions/47540607/disk-i-o-error-with-sqlite3-in-python-3-when-writing-to-a-database