1. Explain why the object-oriented database model was developed.

2. How does the OID in the OO model differ from the primary key in the relational model?

3. Is it possible for a superkey not to be a candidate key? Why or why not?

4. Briefly describe the four types of binary relationships possible between an entity set A and an entity set B based on relationship cardinality (one-to-one, one-to-many, many-to-many, many-to-one).

5. Sales Database:

Customer(custId, lastName, firstName, address, phone, creditLimit)

Order(orderNumber, date, total, custID)

LineItem(orderNumber, itemNumber, qtyOrdered).

Item(itemNumber, itemName, price)

For the Sales Database shown above, write the SQL command to find the name and address of the customer who placed order number 12345.

6. Sales Database:

Customer(custId, lastName, firstName, address, phone, creditLimit)

Order(orderNumber, date, total, custID)

LineItem(orderNumber, itemNumber, qtyOrdered).

Item(itemNumber, itemName, price)

For the Sales Database shown above, write the SQL command to find the item numbers of all items ordered by Sue Adams on June 10, 2015.

Explain why it is necessary to keep recovery logs in a database environment.

How do checkpoints help in recovery?

Why does a DBA create roles?

Explain the three components of the CIA model for information security.