title: Core Data what is created with UIManagedDocument
body: <p>I am unsure about the structure of coreData and how the objects are saved in a directory. So what I know is that you create an instance of UIManagedDocument and make a URL for it and where it will save files. Then you call "SaveToURL", what exactly is created when you call this? is it the core data stack? Then when you save information into the entities you declared is a separate file created within the stack for each set of information in an entity? Finally, what exactly is a context of a UIManagedDocument.</p>
  
  <p>These are the three main questions</p>
  
  <ol>
  <li>What is created when you call "SaveToURL", is it a document or a
  file or a stack?</li>
  <li>When you save information in entities, are separate files created
  within this file/stack?</li>
  <li>what is a UIManagedDocument context?</li>
  </ol>