Question 16 :
(STREET ADDRESS, CITY, STATE, ZIP) is an ideal primary key.
Question 17 :
When the parent entity is required and the parent has a surrogate key, update actions can be ignored.
Question 18 :
When the parent entity is required, a new parent row can always be inserted.
Question 19 :
For every relationship, there are six possible referential integrity actions.
Question 20 :
An ideal primary key is short, numeric and seldom changing.