model.py 文件源码

def get_db_connection():
        if DbHelperM.__db_connection is None:
            DbHelperM.__db_connection = sqlite3.connect(wbd.wbd_global.get_database_filename())

            # Upgrading the database
            # Very good upgrade explanation:
            # http://stackoverflow.com/questions/19331550/database-change-with-software-update
            # More info here: https://www.sqlite.org/pragma.html#pragma_schema_version
            current_db_ver_it = get_schema_version(DbHelperM.__db_connection)
            target_db_ver_it = max(upgrade_steps)
            for upgrade_step_it in range(current_db_ver_it + 1, target_db_ver_it + 1):
                if upgrade_step_it in upgrade_steps:
                    upgrade_steps[upgrade_step_it](DbHelperM.__db_connection)
                    set_schema_version(DbHelperM.__db_connection, upgrade_step_it)
            DbHelperM.__db_connection.commit()

            # TODO: Where do we close the db connection? (Do we need to close it?)
            # http://stackoverflow.com/questions/3850261/doing-something-before-program-exit

        return DbHelperM.__db_connection