title: What is Z_ENT column in SQLite database that gets created by Core Data?
body: <p>When you use Core Data with SQLite database as underlying data store, core data will autogenerate some columns...</p>
  
  <p>One of them is "Z_ENT"  and another is "Z_OPT"</p>
  
  <p>I believe "Z_OPT" is for how many times the record has been altered.  Can anyone tell me what Z_ENT is for?</p>
  
  <p>Thanks!</p>