title: What does the Indexed Property of a CoreData attribute do?
body: <p>I have a Core data model with a 32bit hash value.  I need to look up specific hash values quickly.  Should I use the indexed property?  I have no idea what it does and the <a href="http://developer.apple.com/library/mac/#documentation/cocoa/conceptual/coredata/Articles/cdMOM.html#//apple_ref/doc/uid/TP40002328-SW1" rel="noreferrer">documentation</a> is no help (am I looking in the wrong place?)</p>
  
  <p>So what does indexed do exactly?</p>
  
  <p><img src="https://i.stack.imgur.com/fV0e9.png" alt="model"></p>
  
  <p><img src="https://i.stack.imgur.com/qZGAT.png" alt="enter image description here"></p>