Question

How would I know if the following update executed successfully, right now the statement executes but the table doesn’t reflect that.

cursor = mysql.cursor()
cursor.execute("""UPDATE foo SET key1 = %s  WHERE id = %s""", (val1, id2))

Answer 1

As far as I know, you need to call

mysql.commit()

for your changes to take effect.

This makes sure that your database operations (you can have multiple) are executed in one so called transaction. If something goes wrong, you can revert the whole changes.

In one transaction you put stuff that belong together, like adding a new person and setting a reference to that person in another table.

See also the chapter Insert Operation on this page (where they use rollback in case of an exception): http://www.tutorialspoint.com/python/python_database_access.htm