flask 踩坑记录（持续更新）

1. flask+sqlalchemy 连接mysl

• db.create_all()报错：

  Traceback (most recent call last):
  File “flaskee.py”, line 18, in
  db.create_all()
  File “/home/tylerscope/PycharmProjects/flaskee/venv/lib/python3.6/site-packages/flask_sqlalchemy/init.py”, line 963, in create_all
  self._execute_for_all_tables(app, bind, ‘create_all’)
  File “/home/tylerscope/PycharmProjects/flaskee/venv/lib/python3.6/site-packages/flask_sqlalchemy/init.py”, line 940, in _execute_for_all_tables
  app = self.get_app(app)
  File “/home/tylerscope/PycharmProjects/flaskee/venv/lib/python3.6/site-packages/flask_sqlalchemy/init.py”, line 912, in get_app
  ‘No application found. Either work inside a view function or push’
  RuntimeError: No application found. Either work inside a view function or push an application context. See http://flask-sqlalchemy.pocoo.org/contexts/.

• 原因及解决：

  • 原因：没有找到app。说白了，就是还没有找到实例化的app，就调用了他的功能。
  • 解决：1. 可以在db.create_all()前面、db.init_app(app)后面加一句 db.app=app实例化即可；2. 或者，在视图方法中中调用db.create_all().