Python SQLite: Is Commit() needed for SELECT Queries?

Question

I have made it a habbit that when i do cur.execute() functions, I do a sql.commit() function right after.

Is sql.commit() needed if I do not modify the database (i.e. only do a SELECT query)?

Here is an example:

sql = sqlite3.connect('DB.db')
cur = sql.cursor()
cur.execute('SELECT * FROM table')
sql.commit()

If it a simple select statement like in your example, there is no reason to perform a commit. — idjaw
– idjaw, Commented Nov 16, 2015 at 1:46
Actually, this might help provide more context. Let me know if this was helpful: stackoverflow.com/questions/14430424/commit-after-select — idjaw
– idjaw, Commented Nov 16, 2015 at 1:47
My select queries are simple and do not modify the database. They just pull info. — Bijan
– Bijan, Commented Nov 16, 2015 at 1:53
The example in the docs implies you can use execute: c.execute("SELECT * FROM stocks WHERE symbol = '%s'" % symbol) docs.python.org/2/library/sqlite3.html — Sandwich Heat
– Sandwich Heat, Commented Nov 16, 2015 at 1:57

Colonel Thirty Two · Accepted Answer · 2015-11-16 02:29:26Z

6

Python does not begin a transaction for select statements.

From the Transaction control section of the sqlite3 module docs:

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).

answered Nov 16, 2015 at 2:29

Colonel Thirty Two

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1 Comment

linrongbin Over a year ago

(since english is not my mother tongue, I'm confused by the latter part of this doc) does and commits transactions implicitly before a non-DML, non-query statement means sqlite3 will implicitly do commits for both non-DML (insert/delete/update/create) and non-query (anything other than select) ?

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