Yeah , you are absolutely correct. It will allow me to delete the record from UserInfo Table but not TRUNCATE it

and i still wonder what is the explanation from Microsoft in not allowing me to Truncate the Table when i beleive that TRUNCATE will recreate the complete structure , reseed the identity and recreate all constraints.

Now having said this. My Ultimate Objective to add the constraint is just to speed up my query execution. so that when ever i pick UserInfo and put a join with Country Table , having foreign key will speed up the process.

BUT

I still wonder if its a good decision to add such a relation or Some expert can question this decision.

Thanks

Zubair