title: Difference between transient and derived properties of a core data entity
body: <p>What is the difference between transient and derived properties of a core data entity? I would like to create a "virtual" property that can be used in a fetch operation to return localized country names from a core data entity. </p>
  
  <p>The operation is to be done this way:</p>
  
  <ol>
  <li>retrieve the country name from the database in english</li>
  <li>do a NSLocalizedString(countryNameInEnglish, nil) to obtain the localized country name.</li>
  </ol>
  
  <p>2 is to be done by this "virtual" property.</p>
  
  <p>Which one should I use? transient or derived and how do I do that?</p>
  
  <p>I have nothing to show you because I have no clue what I should use. </p>
  
  <p>thanks</p>