Database Reference
In-Depth Information
24. What is replication? What is synchronization?
25. Describe three utility services that a DBMS should provide.
26. What is a procedural language? What is a nonprocedural language?
Premiere Products Exercises
For the following exercises, you will address problems and answer questions from management at Premiere Pro-
ducts. You do not use the Premiere Products database for any of these exercises.
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1. While users were updating the Premiere Products database, one of the transactions was interrupted. You need
to explain to management what steps the DBMS will take to correct the database. Using the sample log in
Figure 7-11, list and describe the updates that the DBMS will roll back if transaction 2 is interrupted at 8:10.
2. Occasionally, users at Premiere Products obtain incorrect results when they run queries that include built-in
(aggregate, summary, or statistical) functions. The DBA told management that unrepeatable reads caused the
problems. Use books, articles, and/or the Internet to research the unrepeatable read problem. Write a short
report that explains the unrepeatable-read problem to management and use an example with your explanation.
(Note: Unrepeatable reads are also called inconsistent retrievals, dirty reads, and inconsistent reads.)
3. You've explained replication to management, and some managers ask you for examples of when replication
could be useful to them. Describe two situations, other than the ones given in the text, when replication would
be useful to an organization.
4. The staff of the marketing department at Premiere Products is scheduled to receive some statistical databases,
and they need you to explain these databases to them. (A statistical database is a database that is intended to
supply only statistical information to users; a census database is an example of a statistical database.) Using a
statistical database, users should not be able to infer information about any individual record in the database.
Use books, articles, and/or the Internet to research statistical databases; then write a report that explains them,
discusses the problem with using them, and gives the solution to the problem.
5. The DBA at Premiere Products wants you to investigate biometric identification techniques for potential use at
the company for computer authentication purposes. Use books, articles, and/or the Internet to research these
techniques, then write a report that describes the advantages and disadvantages of each of these techniques.
In addition, recommend one technique and provide a justification for your recommendation.
Henry Books Case
Ray Henry plans to upgrade his database and wants you to help him select a different DBMS. To help him, he
would like you to complete the following exercises. You do not use the Henry Books database for any of these
exercises.
1. Many computer magazines and Web sites present comparisons of several DBMSs. Find one such DBMS com-
parison and compare the functions in this chapter to the listed features and functions in the comparison. Which
functions from this chapter are included in the comparison? Which functions are missing from the comparison?
What additional functions are included in the comparison?
2. How well does your school's DBMS fulfill the functions of a DBMS as described in this chapter? Which functions
are fully supported? Which are partially supported? Which are not supported at all?
3. Use computer magazines and/or the Internet to investigate one of these DBMSs: DB2, SQL Server, MySQL,
Oracle, or Sybase. Prepare a report that explains how that DBMS handles the following DBMS functions: con-
current update, data recovery, and security. (Note: For concurrent update, you might need to review the concur-
rency control features of the DBMS.)
Alexamara Marina Group Case
For the following exercises, you will address problems and answer questions from the Alexamara Marina Group
staff. You do not use the Alexamara database for any of these exercises.
