title: How are dates stored in Oracle?
body: <p>How are dates stored in Oracle? For example I know most systems use Epoch time to determine what time it is. By calculating how many seconds away from January 1st 1970. Does Oracle do  this as well? </p>
  
  <p>The reason I am asking this is I noticed if you take two dates in Oracle and subtract them you get a floating point of how many days are between. </p>
  
  <p>Example</p>
  
  <pre><code>(Sysdate - dateColumn)
  </code></pre>
  
  <p>would return something like this (depending on the time)</p>
  
  <pre><code>3.32453703703703703703703703703703703704
  </code></pre>
  
  <p>Now is Oracle doing the conversion and spitting that format out, or does Oracle store dates with how many days it is away from a certain time frame? (Like Epoch time)</p>