surfinhu 0 Report post Posted July 8, 2008 Hi i am new,I have a problem in understanding the query decomposition in D-DB. Can anyone help me to understand the first question of the exercise 25.21 of Elmasri-Navath 4th edition?Consider the following relations:BOOKS (Book#, Primary_author, Topic, Total_stock, $price)BOOKSTORE (Store#, City, State, Zip, Inventory_value)STOCK (Store#, Book#, Qty)Consider a distributed database for a bookstore chain called National Books with 3 sites called EAST, MIDDLE, and WEST.Consider that BOOKS are fragmented by $price amounts into:B1:BOOK1:up to $20.B2:BOOK2:from 20.01 to $50.B3:BOOK3:from 50.01 to $100.B4:BOOK4100.01 and above.Similarly, BOOKSTORES are divided by Zipcodes into:S1:EAST:Zipcodes up to 35000.S2:MIDDLE:Zipcodes 35001 to 70000.S3:WEST:Zipcodes 70001 to 99999.Assume that STOCK is a derived fragment based on BOOKSTORE only.a. Consider the query:SELECT Book#, Total_stockFROM BooksWHERE $price > 15 and $price < 55;Assume that fragments of BOOKSTORE are non-replicated 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). Share this post Link to post Share on other sites
yordan 10 Report post Posted July 9, 2008 Is this a conceptual understanding problem ? Or is it an exercise a teacher asked you to perform ? In the second case, not sure the answer will arrive before the deadline... Share this post Link to post Share on other sites
