I am using coredata framework. In my NSManagedObjectModel i am using three entities that are Class, Student and Score where class and student have one-to-many & inverse relationship and Student and Score have also inverse but one-one relationship.

Score entity has all optional attributes and having default '0' decimalVaue, which is not assigned at the time new Student is added. But later i want to assign them score individually and also to particular attribute not all of score attributes in a go. I am able to create and add Students to particular Class but dont have any idea how to call particular student and assign them score. For example I want to assign Score'attribute "dribbling" [there are many attributes like "tackling"] a decimal value to Student "David" of Class "Soccer" ,how i can do that?

Thanks in advance for any suggestion.