Simple sqlite3 context manager for Python.

withsqlite.py

#!/usr/bin/env python

import sqlite3

class dbopen(object):
    """
    Simple CM for sqlite3 databases. Commits everything at exit.
    """
    def __init__(self, path):
        self.path = path

    def __enter__(self):
        self.conn = sqlite3.connect(self.path)
        self.cursor = self.conn.cursor()
        return self.cursor

    def __exit__(self, exc_class, exc, traceback):
        self.conn.commit()
        self.conn.close()


if __name__ == '__main__':
    with dbopen('./sample.db') as c:
        c.execute("CREATE TABLE seekmap (id text, offset int, length int)")
        c.execute("INSERT INTO seekmap VALUES ('a', 0, 2000)")
        c.execute("INSERT INTO seekmap VALUES ('b', 2000, 3000)")
        c.execute("SELECT * FROM seekmap")
        result = c.fetchall()
        print(result)
        # [(u'a', 0, 2000), (u'b', 2000, 3000)]

self .conn = None
self .cursor = None

Why?

@Glukhov555, you're right, it's not necessary - I changed the code. I'd say it would be ok to document the attributes in the constructor.

need to mark that it is not necessary but, for the understanding of how it is taken would not be bad

Thank you for that.

Thank you!

I have made a gist with this updated to have type hinting fwarren / withsqlite.py and to pass linting. __init__ needs self.conn and self.cursor but they are not initalized, only type hinted.

self.conn: Connection
self.cursor: Cursor

In actual practice you can typehint execute(), fetchall(), fetchmany() and fetchone() with:

result: Cursor = c.execute()
result: list[Any] = c.fetchall()
result: list[Any] = c.fetchmany()
result: Any = c.fetchone()