joins in coredata using Objective C

How to make inner joins,outer joins(left,right,full) in core-data. I have done it easily in sqlite db using sqlite c based APIs But I couldn't find any resources on how to do it using core-data in Objective C.

Basically I have a need to query CoreData that involves relation between more than three tables or objects.

Note:

How to set relationship between tables in core-data would be helpful. such as Primary key - foreign key relationship,cascade relationship.