title: Android app using Google cloud Endpoints: Datastore vs SQL
body: <p>I want to develop a new Android application and I was wondering about the architecture to use.
  My idea is to host my app on Google App Engine, using the Google Cloud Endpoints as backend.
  The only problem is that Google Cloud Endpoints use Google Datastore (that is a non-relational database, while I wanted to use a relational one). </p>
  
  <p>So my questions are: </p>
  
  <p>-Is there the possibility to change the logic of Google Cloud Endpoints using Google Cloud SQL ?</p>
  
  <p>-If not, is there the possibility to use Google Datastore in a relational way (with references between tables) ?</p>
  
  <p>Thanks.</p>