The solutions to the remaining problems follow the same format as Problem 8. However, Problem 11 requires you to do some research about the information that goes in the transcript data. Use your creativity and analytical skills to research and create a simple XML file containing the data that are customary on your university transcript.
Chapter 15
Database Administration and Security
Answers to Selected Review Questions
2. This question is answered in Section 15.1, Data as a Corporate Asset. The interactions are illustrated in Figure 15.1.
The end user's role is important throughout the process. The end user must analyze data to produce the information that is later used in decision making. Most business decisions create additional data that will be used to monitor and evaluate the company situation. Thus, data will or should be recycled to produce feedback about an action's effectiveness and efficiency.
3. The first step would be to emphasize the importance of data as a company asset, which should be managed like any other asset. Top-level managers must understand this crucial point and be willing to commit company resources to manage data as an organizational asset.
The next step is to identify and define the need for and role of the DBMS in the organization. Review Section 15.2, The Need for and Role of Databases in an Organization, and apply the concepts discussed there to any organization. (For example, if you are interested in real estate sales organizations, apply the concepts to that organization.) Managers and end users must understand how the DBMS can enhance and support the work of the organization at all levels (top management, middle management, and operational).
Finally, illustrate and explain the impact of a DBMS introduction into an organization. Refer to Section 15.3, Introduction of a Database: Special Considerations, to accomplish that task. Note particularly the technical, managerial, and cultural aspects of the process.
6. Security means protecting data against accidental or intentional use by unauthorized users. Privacy deals with the rights of people and organizations to determine who accesses the data and when, where, and how the data are to be used.
The two concepts are closely related. In a shared system, individual users must ensure that the data are protected from unauthorized use by other individuals. Also, the individual user must have the right to determine what, when, where, and how other users use the data. The DBMS must provide the tools that allow for flexible management of the data security and access rights in a company database.
8. See Section 15.3, Introduction of a Database: Special Considerations. Students may hold a discussion about the special considerations (managerial, technical, and cultural) that should be considered when a new DBMS is introduced in an organization. For example, the discussion may focus on the following questions:
• What retraining is required for the new system? ¾ Who needs to be retrained?
¾ What type and extent of retraining is needed? • Is it reasonable to expect some resistance to change:
¾ From assistants?
¾ From technical support personnel? ¾ From other departmental end users? • How might the resistance be manifested? • How can you deal with such resistance?
11. See Section 15.5, The Database Environment’s Human Component, particularly Section 15.5.2, The DBA’s Technical Role. Then tie that discussion to the increasing use of Web applications.
The DBA’s function may be one of the most dynamic functions of any organization. New technological developments constantly change the DBA’s role. For example, note how each of the following has an effect on the DBA’s function:
• Development of the DDBMS. • Development of the OODBMS. • Increased use of LANs.
• Rapid integration of intranet and extranet applications and their effects on database design, implementation, and management (Security issues become especially important.)
15. See Section 15.5, especially Table 15.2.
25. See Section 15.5.2. Database performance tuning is part of the maintenance activities. As the database system enters into operation, the database starts to grow. Resources initially assigned to the application are sufficient for the initial loading of the database. As the system grows, the database becomes bigger, and the DBMS requires additional resources to satisfy the demands on the larger database. Database performance will decrease as the database grows and more users access it.
28. See Section 15.6.2. See also Table 51.4 for a sample security vulnerability and related measures.
35. See Section 15.9.4. Here is a summary. • A tablespace is a logical storage space.
• Tablespaces are primarily used to logically group related data. • Tablespace data are physically stored in one or more datafiles.
37. See Section 15.9.4. Here is a summary.
• A database is composed of one or more tablespaces. Therefore, there is a 1:M relationship between the database and its tablespaces.
• Tablespace data are physically stored in one or more datafiles. Therefore, there is a 1:M relationship between tablespaces and datafiles.
• A datafile physically stores the database data.
• Each datafile is associated with one and only one tablespace. (But each datafile can reside in a different directory on the same hard disk—or even on different disks.)
In contrast to the datafile, a file system's file is created to store data about a single entity, and the programmer can directly access the file. But file access requires the end user to know the structure of the data that are stored in the file.
While a database is stored as a file, the file is created by the DBMS, rather than by the end user. Because the DBMS handles all file operations, the end user does not know—nor does the end user
need to know—the database's file structure. When the DBA creates a database—or, more accurately,
uses the Oracle Storage Manager to let Oracle create a database—Oracle automatically creates the necessary tablespaces and datafiles.
The basic database components have been summarized logically in Figure Q15.37sol.