I had good relations with my teachers. This is past, I no longer have this relationship. This is appropriate because in your example the relationship ended in 2006.
I had a book --- I used to have a book, but not any more.
I had a cordial relationship with him --- Even this means that relationship no more holds?
I have a cordial relationship with him.. this is again clear for me. This talks about the current status.
Student or Learner