Given the following database scheme:
CUSTOMER (Cust#, Cust_Name, Cust_City)
ORDER (Order#, Ord_Date, Cust#, Ord_Amt)
ORDER_ITEM (Order#, Item#, Qty)
ITEM (Item#, Item_Name, Unit_Price)
SHIPMENT (Order#, Warehouse#, Ship_Date)
WAREHOUSE (Warehouse#, Warehouse_City)
WareHOUSE_ITEM (Item#, Warehouse#, Qty)
Write down relational expressions (either relational algebra or relational calculus) for the following queries.
(a) List Order#, Ord_Date and Ship_Date for orders which have not been shipped. You can use CURRENT_DATE as the value of the current system date and time.
(b) List Order# and Warehouse_City from customers who live in Brisbane.
(c) Produce a list of Item# that has never been ordered.
(d) List Item_Name and Qty that are stored in all warehouses in Sydney.
(e) List the most popular item(s) being ordered.
A PARTS file with Part# as the key field includes records with the following Part# values: 37, 11, 6, 12, 8, 26, 16, 35, 22, 1, 9, 4, and 27. Suppose that the search field values are inserted on the given order in a B+ tree of order p = 3 and Pleaf = 2.
(a) Show how the tree will expand after each inserted value and what the final tree will look like.
(b) Delete the following values: 26, 12, 1, 37, 9, 11, 35, and 6. Show how the tree will shrink after each deleted value in the given order and show the final tree.