SQLite executemany或联合选择可减少数据库写入

Question

I'm trying to reduce the number of writes to a Sqlite database when it comes to inserting multiple rows into a table.

I've found two methods of doing this so far, using a union select statement or using the executemany command in sqlite3.

Does executemany work via a single write?

For reference, please see the following statement I'm using (union select):

INSERT INTO table1
SELECT "hello" AS field1, 15 AS field2, 1262340000 AS timestamp 
UNION SELECT "byebye", 10, 1262340000 
UNION SELECT "hi", 20, 1262340000 
UNION SELECT "boo", 25, 1262340000 

UPDATE

I'm aware building an SQL statement via string concatenation is really bad from a security point of view but in this case, the database owner is also the data provider so SQL injection issues can be ignored.

This is for Python 2.7

sqlite3 version 2.6.0

Answer 1

SQLite flushes data from its page cache to disk when the transaction commits. So you just need to put all the INSERTs into a single transaction:

BEGIN;
INSERT INTO table1 VALUES('hello', 15, 1262340000);
INSERT INTO table1 VALUES('byebye', 10, 1262340000);
INSERT INTO table1 VALUES('hi', 20, 1262340000);
INSERT INTO table1 VALUES('boo', 25, 1262340000);
COMMIT;

Python automatically inserts transactions behind your back , so you can just use a bunch of execute() s, or executemany() :

data = [('hello', 15, 1262340000),
        ('byebye', 10, 1262340000),
        ('hi', 20, 1262340000),
        ('boo', 25, 1262340000)]
con.executemany("INSERT INTO table1 VALUES(?, ?, ?);", data)
con.commit()