如何判断Python SQLite数据库连接或游标是否已关闭？

Question

假设您有以下代码:

import sqlite3

conn = sqlite3.connect('mydb')
cur = conn.cursor()
# some database actions
cur.close()
conn.close()
# more code below

如果我稍后尝试使用conn或cur对象,我怎么能告诉它们已关闭？我找不到.isclosed()方法或类似的东西.

Answer 1

你可以在try, except声明中包装:

>>> conn = sqlite3.connect('mydb')
>>> conn.close()
>>> try:
...   resultset = conn.execute("SELECT 1 FROM my_table LIMIT 1;")
... except sqlite3.ProgrammingError as e:
...   print e
Cannot operate on a closed database.

这依赖于特定于sqlite3的快捷方式.