Example of Restricted
Suppose we have two tables (Customer & Order) and the relation is of One-To-Many i.e Customer can have many orders.
So on a parent table i.e.(Customer) if I set a delete action property to "RESTRICTED" for Order table. Then If I go and delete the record from a Customer table. It will first check the record in the child table and if exist that warning prompt saying that first we need to delete a record from child table.
Reference:
https://amazingax.wordpress.com/2013/01/13/microsoft-dynamics-ax-2012example-of-cascaderestricted-and-cas