1. Design a database diagram for a product orders database with four tables. Indicate the relationships between tables and identify the primary key and foreign keys in each table. Explain your design decisions. Customers Orders OrderLineItems CustomerID CustomerName CustomerAddress CustomerPhone . . . OrderID CustomerID OrderDate ShipAddress ShipDate . . . OrderID OrderSequence ProductID Quantity UnitPrice Products ProductID ProductName QtyPerUnit UnitPrice InStock OnOrder . . . 2. Add the two tables below into the design for exercise 1. Create additional tables and columns, if necessary. Explain your design decisions. Shippers Employees ShipperID ShipperName ShipperAddress ShipperPhone . . . Em ployeeID FirstName LastName SSN HireDate . . . 3. Modify your design for exercise 2 to identify the columns that should be indexed, and explain your decisions.