title: CoreData customize mapping model
body: <p>I have a problem mapping the following situation from v1 to v2 of a core data model.</p>
  
  <p>In v1 of the model I had an entity named book with an attribute author. There I saved the first and last name of the author and even first and last names of several authors. Very poor design I know, but that's how it was.</p>
  
  <p>In v2 of the model I made it better and added the entity author with the attributes firstname and lastname and a relationship to book. Does anyone know out there how I can customize the mapping model in such a manner, that it calls a function (which returns the number of authors and the first and last name separated) and creates the new entities regarding to the output of that function?</p>
  
  <p>Thanks
  b00tsy</p>