13.26. Consider the Standard Price List in Figure 13-9.a. Write an SQL statement that will increase...

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13.26. Consider the Standard Price List in Figure 13-9.
a. Write an SQL statement that will increase the UnitPrice
of PartNumber 98756 by 10 percent.
. Indicate whether the statement you wrote in part a is
acceptable under each of the following:
• Remote unit of work
• Distributed unit of work
• Distributed request
13-27. Consider the four parts databases in Figure 13-9.
a. Write an SQL statement that will increase the Balance
in PartNumber 98765 in Tulsa Parts by 20 percent
and another SQL statement that will decrease the
Balance in PartNumber 12345 in New York Parts by
20 percent.
. Indicate whether the statement you wrote in part a is
acceptable under each of the following:
• Remote unit of work
• Distributed unit of work
• Distributed request
13-31. Consider the SUPPLIER, PART, and SHIPMENT relations and distributed database mentioned in the section on query optimization in this chapter.
a. Write a global SQL query (submitted in Columbus) to display the PartNumber and Color for every part that is not supplied by a supplier in Chicago.
. Design three alternative query-processing strategies for your answer to part a.
c. Develop a table similar to Table 13-2 to compare the processing times for these three strategies.
d. Which of your three strategies was best and why?
e. Would data replication or horizontal or vertical partitioning of the database allow you to create an even more efficient query-processing strategy? Why or why not?

a1-x22taz3c.docx

Sandeep Kumar · Accepted Answer

13-26. Figure 13-9 Standard Price List questions
a.
UPDATE   Part_T
SET      UnitPrice = UnitPrice * 1.10
WHERE    PartNumber = 56789;
b.
i.  Not acceptable. The remote unit of work allows updates at a single
remote computer. Thus, updates cannot be made simultaneously at
more than one location—three in the case of Figure 13-9. 
ii.  Not   acceptable.   The   distributed   unit   of   work   allows   various
statements   within   a   unit   of   work   to   refer   to   multiple   remote
locations.   Updates   however,   cannot   be   made   simultaneously   at
more   than   one   location   because   all   tables   in   a   single   SQL
statement must be at the same location. 
iii.  Acceptable. A distributed request allows a single SQL statement to
refer to tables at more than one remote DBMS.
13-27 Figure 13-9 Parts databases questions
a.
UPDATE   Part_T
SET      Balance = Balance * 1.20
   WHERE    PartNumber = 98765 AND Location = "Tulsa";
   UPDATE   Part_T
   SET      Balance = Balance * .8
   WHERE    PartNumber = 12345 AND Location = "New York";
Chapter 13
b.
i.   Not acceptable. The transaction in 3a. is essentially a sequence of
SQL  statements   originated  at  one  location,   but attempted  to  be
executed by multiple remote  DBMSs. The remote unit of work
protocol would support only transactions attempted to be executed
at a single remote location, and in addition, the same DBMS has to
run on the remote computer.
ii.  Acceptable.  The distributed  unit of   work protocol   does  support
protected updates involving multiple sites, provided that each SQL
statement refers to table(s) at one site only.
iii.  Cannot determine.

13.26. Consider the Standard Price List in Figure 13-9. a. Write an SQL statement that will increase the UnitPrice of PartNumber 98756 by 10 percent. b. Indicate whether the statement you wrote in...

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