为什么要在Python中关闭Sqlite3的游标 [英] Why close a cursor for Sqlite3 in Python

问题描述

使用Python的 sqlite3模块？还是仅仅是 DB API v2.0 的产物对其他数据库有用吗？

Is there any benefit to closing a cursor when using Python's sqlite3 module? Or is it just an artifact of the DB API v2.0 that might only do something useful for other databases?

有意义的是 connection.close（）释放资源；但是，目前尚不清楚 cursor.close（）的实际作用，它实际上是释放一些资源还是什么都不做。

It makes sense that connection.close() releases resources; however, it is unclear what cursor.close() actually does, whether it actually releases some resource or does nothing. The docs for it are unenlightening:

>>> import sqlite3
>>> conn = sqlite3.connect(':memory:')
>>> c = conn.cursor()
>>> help(c.close)
Help on built-in function close:

close(...)
    Closes the cursor.

请注意，这是与为什么需要创建游标？ 。我知道游标的用途。问题在于cursor.close（）方法的实际作用以及调用它是否有任何好处。

Note, this is a completely different question than Why do you need to create a cursor when querying a sqlite database?. I know what cursors are for. The question is about what the cursor.close() method actually does and whether there is any benefit to calling it.

推荐答案

在对于SQLite，没有太大区别，但是数据库API不仅适用于嵌入式数据库，而且适用于所有SQL数据库。

In the case of SQLite, there isn't much difference but the API for databases is not just for embedded databases but for all SQL databases.

对于DBMS，通常使用游标

For a DBMS, a cursor often implies a session in the client and sometimes on the server.

因此，如果您不使用Python的引用计数实现（例如CPython），则很多资源可能会被占用，直到GC释放它们。

So, if you are not using a reference counting implementation of Python (such as CPython), then a lot of resources could be tied up until GC frees them.

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