env.py 文件源码

def run_migrations_online():
    """Run migrations in 'online' mode.

    In this scenario we need to create an Engine
    and associate a connection with the context.
    """
    engine = db_api.get_engine()
    connection = engine.connect()
    target_metadata = db_models.MeteosBase.metadata
    context.configure(connection=connection,  # pylint: disable=E1101
                      target_metadata=target_metadata)
    try:
        with context.begin_transaction():  # pylint: disable=E1101
            context.run_migrations()  # pylint: disable=E1101
    finally:
        connection.close()