无法从我的脚本中删除 .db 文件，但可以从其他任何地方删除

Question

如果我运行下面的脚本，它会抛出显示的错误。但是，如果我切换终端并运行相同的命令来删除文件 (os.remove("test.db"))，则会删除该文件。

import gc
import os
import time

from sqlite3 import connect
from contextlib import contextmanager


file = "test.db"


@contextmanager
def temptable(cur: object):
    cur.execute("create table points(x, int, y int)")
    try:
        yield
    finally:
        cur.execute("drop table points")


with connect(file) as conn:
    cur = conn.cursor()
    with temptable(cur=cur):
        cur.execute("insert into points (x, y) values(1, 1)")
        cur.execute("insert into points (x, y) values(1, 2)")
        cur.execute("insert into points (x, y) values(2, 1)")
        for row in cur.execute("select x, y from points"):
            print(row)
        for row in cur.execute("select sum(x * y) from points"):
            print(row)

os.remove(file)

文件“c:\Users\You_A\Desktop\2019Coding\context_generator_decorator.py”，第 32 行，在 os.remove（文件） PermissionError: [WinError 32] 进程无法访问该文件，因为它正被另一个进程使用：'test.db'

同样，在任何终端中运行 os.remove("test.db") 会成功删除文件。

Answer 1

这可能是由于与数据库的连接没有关闭造成的。尝试使用contextlib.closing()。修改后的代码看起来像，

import gc
import os
import time

from sqlite3 import connect
from contextlib import contextmanager, closing


file = "test.db"


@contextmanager
def temptable(cur: object):
    cur.execute("create table points(x, int, y int)")
    try:
        yield
    finally:
        cur.execute("drop table points")


with closing(connect(file)) as conn:
    # cur = closing(conn.cursor()) --> if auto-closing of cursor is desired
    cur = conn.cursor() # if auto closing of cursor is not desired
    with temptable(cur=cur):
        cur.execute("insert into points (x, y) values(1, 1)")
        cur.execute("insert into points (x, y) values(1, 2)")
        cur.execute("insert into points (x, y) values(2, 1)")
        for row in cur.execute("select x, y from points"):
            print(row)
        for row in cur.execute("select sum(x * y) from points"):
            print(row)

os.remove(file)