初始化扩展，传入程序实例 app 设置数据库 URI 第 5 章：数据库 35 为了设置 Flask、扩展或是我们程序本身的一些行为，我们需要设置和定义一些配 置变量。Flask 提供了一个统一的接口来写入和获取这些配置变 量： Flask.config 字典。配置变量的名称必须使用大写，写入配置的语句一般 会放到扩展类实例化语句之前。 下面写入了一个 SQLALCHEMY_DATABASE_URI

just create a new folder yourapplication inside the existing one and move everything below it. Then rename yourapplication.py to __init__.py. (Make sure to delete all .pyc files first, otherwise things would

just create a new folder yourapplication inside the existing one and move everything below it. Then rename yourapplication.py to __init__.py. (Make sure to delete all .pyc files first, otherwise things would