title: Sonar database structure & sonar api metrics
body: <p>I have two questions regarding sonar:</p>
  
  <ol>
  <li><p>I have taken a look at the database of sonar. I was wondering where sonar stores the results of each measurement? </p>
  
  <p>I found only the table <code>measure_data</code>, but the field data looks to me like a has value.
  Can anyone tell me where sonar stores the data of all measurements?</p>
  
  <p>Yes I know, that it is better to use the REST API, and I will do it, but I also want to know, how the database is used by sonar itself.</p></li>
  <li><p>Is there a way by using the API to get a full list of all used metrics?</p></li>
  </ol>