title: Metrics-Database Number Saving Conventions?
body: <p>I want to save metrics (statistics) every day for some processes on my website to display them later in graphs. Example for Metrics might be:</p>
  
  <pre><code>FacebookLikes
  SiteVisitors
  </code></pre>
  
  <p>Now I want to know how to design the MySQL Table. - Whether I should save the "DeltaFacebookLikes" and "DeltaSiteVisitors" - or whether I should save the absolute numbers which keep growing by each entry:  </p>
  
  <pre><code>ID    DATE    FACEBOOK_LIKES    SITE_VISITORS
  </code></pre>
  
  <p>The first example (saving the delta values) would be:<br>
  The problem here is that I would never have the "total" values - unless I sum them up.</p>
  
  <pre><code>1    23.10    33                50
  2    24.10    14                80
  3    25.10    12                5
  4    26.10    28                105
  </code></pre>
  
  <p>The second example (saving the absolute values) would be:<br>
  The problem here is that I have the total values, but I would need to subtract v(x) from v(x+1) to archive the actual delta value.</p>
  
  <pre><code>1    23.10    33                50
  2    24.10    47                130
  3    25.10    59                135
  4    26.10    87                240
  </code></pre>
  
  <p>What would be the right/wrong way? Is there any wrong way?<br>
  Or make both combined sense?</p>