如何在Python中锁定sqlite3数据库？

Question

有没有办法在Python中显式获取sqlite3数据库的锁？

Answer 1

我们可以使用多进程命令来锁定数据库的读写进程。我使用以下命令，它工作正常。 从多处理导入锁 l、 锁定（） l、 获取（） 读/写数据库 l、 释放（）

Answer 2

显式锁定数据库的方法是启动事务，如documentation中所述：

When a database is accessed by multiple connections, and one of the processes modifies the database, the SQLite database is locked until that transaction is committed.

启动事务的一种方法是使用connection as a context manager：

import sqlite3
con = sqlite3.connect(...)
...
with con:
    # Database is locked here

还要注意，默认情况下会发生一些事务implictly：

By default, the sqlite3 module opens transactions implicitly before a Data Modification Language (DML) statement (i.e. INSERT/UPDATE/DELETE/REPLACE), and commits transactions implicitly before a non-DML, non-query statement (i. e. anything other than SELECT or the aforementioned).

Answer 3

在sqlite常见问题解答中，"Can multiple applications or multiple instances of the same application access a single database file at the same time?"：

Multiple processes can have the same database open at the same time. Multiple processes can be doing a SELECT at the same time. But only one process can be making changes to the database at any moment in time, however.

无论是否使用with connection构造，在任何给定时间，只有一个进程可以从中读取数据并写入数据库。