Consider a distributed database for a bookstore chain called National Books with three sites called EAST, MIDDLE, and WEST. The relation schemas are given in Exercise. Consider that BOOKS are fragmented by Splice amounts into:

B1: BOOK1: $price up to $20

B2: BOOK2: $price from $20.01 to $50

B3: BOOK3: $price from $50.01 to $100

B4: BOOK4: $price $100.01 and above.

Similarly, BOOK_STORES are divided by zip codes into:

S1: EAST: Zip up to 35000.

S2: MIDDLE: Zip 35001 to 70000.

S3: WEST: Zip 70001 to 99999.

Assume that STOCK is a derived fragment based on BOOKSTORE only.

a. Consider the query:

SELECT Book#, Total _stock

FROM Books

WHERE $price > 15 AND $price<55;

Assume that fragments of BOOKSTORE are nonreplicated and assigned based on region. Assume further that BOOKS are allocated as:

EAST: B1, B4

MIDDLE: B1, B2

WEST: B1, B2, B3, B4

Assuming the query was submitted in EAST, what remote subqueries does it generate? (Write in SQL.)

b. If the price of Book# = 1234 is updated from $45 to $55 at site MIDDLE, what updates does that generate? Write in English and then in SQL.

c. Give a sample query issued at WEST that will generate a subquery for MIDDLE.

d. Write a query involving selection and projection on the above relations and show two possible query trees that denote different ways of execution.

Exercise

Consider the following relations:

BOOKS(Book#, Primary_author, Topic, Total_stock, splice)

BOOKSTORE(Store#, City, State, Zip, Inventory_value)

STOCK(Store#, Book#, Qty)

Total stock is the total number of books in stock, and Inventory_value is the total inventory value for the store in dollars.

Answer rating: 100% (QA)

a Consider the following SQL query to find Book from STOCK of those book which are submitted in EAST SQL Query select Book Totalstock from BOOKS where Book inselect Book from STOCK where Store inselec... View the full answer