title: Programmatically Update an attribute in Core Data
body: <p>I've looked through all the class documentation for Core Data and I can't find away to programmatically update values in a core data entity. For example, I have a structure similar to this:</p>
  
  <pre><code> id  | title
  ============
    1  | Foo  
    2  | Bar  
    3  | FooFoo
  </code></pre>
  
  <p>Say that I want to update Bar to BarBar, I can't find any way to do this in any of the documentation.</p>