如何判断 Python SQLite 数据库连接或游标是否已关闭？
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How to tell if Python SQLite database connection or cursor is closed?
提问by daveslab
Let's say that you have the following code:
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
If I try to use the connor curobjects later on, how could I tell that they are closed? I cannot find a .isclosed()method or anything like it.
如果我稍后尝试使用conn或cur对象，我怎么知道它们已关闭？我找不到.isclosed()方法或类似的东西。
采纳答案by mechanical_meat
You could wrap in a try, exceptstatement:
你可以用一个try, except语句换行：
>>> 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.
This relies on a shortcut specific to sqlite3.
这依赖于特定于 sqlite3的快捷方式。
回答by quamrana
How about making sure that the connection and cursor are never closed?
如何确保连接和游标永远不会关闭？
You could have a state based program that you can guarantee only calls close() at the right time.
你可以有一个基于状态的程序，你可以保证只在正确的时间调用 close() 。
Or wrap them in other objects that have a pass implementation of close(). Or add an _isclosedmember set by close()and accessed by isclosed().
或者将它们包装在具有传递实现的其他对象中close()。或添加由_isclosed设置close()和访问的成员isclosed()。
