title: Flask, SQLAlchemy : KeyError: 'SQLALCHEMY_TRACK_MODIFICATIONS'
body: <p>I am trying to follow the instructions from the following tutorial:</p>
  
  <p><a href="https://medium.com/@rodkey/deploying-a-flask-application-on-aws-a72daba6bb80" rel="noreferrer">Tutorial</a></p>
  
  <p>I downloaded the code from the following repo:</p>
  
  <p><a href="https://github.com/inkjet/flask-aws-tutorial" rel="noreferrer">Repo</a></p>
  
  <p>However when I run it locally and try to add something to the database, I get the following error:</p>
  
  <pre><code>builtins.KeyError
  KeyError: 'SQLALCHEMY_TRACK_MODIFICATIONS'
  </code></pre>
  
  <p>When I tried to read the traceback, I realised that even if I add a variable SQLALCHEMY_TRACK_MODIFICATIONS to the config file, some python library file is unable to recognise it exists.</p>
  
  <p>Looks like there is another answer to a similar question, but that was more like a quick fix, not why this is happening.</p>
  
  <p>I would like to know why this is happening and how to fix it.Preferably without changing the whole structure.</p>
  
  <p>Thanks a lot in advance.</p>