For the following exercises, you will address problems and answer questions from management at TAL Distributors.
You do not use the TAL Distributors database for any of these exercises.
1. While users were updating the TAL Distributors 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 shown 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 TAL Distributors 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. (Unrepeatable reads are also called inconsistent retrievals, dirty reads, and inconsistent reads.)
3. Youve 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 TAL Distributors 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 TAL Distributors wants you to investigate bio metric 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.
6. Because most reps access the TAL Distributors database from their mobile devices, such as smart phones and tablets, the DBA is considering the potential use of cloud computing. Use books, articles, and/or the Internet to research cloud computing, then write a report that describes the advantages and disadvantages of making data available in the cloud.