Chapter 10 Solution

Discovering Computer 2011 – Living in a Digital World
Page 545-546
Lecturer : Tri Djoko Wahjono

True/False

  1. Data is a collection of unprocessed items, which can include text, numbers, images, audio, and video. (True)
  2. A database management system allows users to create forms and reports from the data in the database. (True)
  3. A range check ensures users enter only numeric data in a field. (False)
  4. A check digit often confirms the accuracy of a primary key value. (True)
  5. Databases require less memory, storage, and processing power than a file processing system. (False)
  6. A report is a window on the screen that provides areas for entering or modifying data in a database. (False)
  7. Continuous backup is a backup plan in which all data is backed up whenever a change is made. (True)
  8. A relationship is a link within the data in a database. (True)
  9. Normalization is a process designed to ensure the data within the relations (tables) is duplicated so that it is not lost. (False)
  10. The data in a distributed database exists in many separate locations throughout a network or the Internet. (True)

Multiple Choice

  1. B. Timely
  2. A. Composite key
  3. D. File maintenance
  4. B. Determines whether a number is within a specified range
  5. A. Less complexity
  6. B. Data dictionary
  7. B. Principle of least privilege
  8. A. Decides on the proper placement of field

Matching

  1. Field name, e. uniquely identifies each field
  2. Field size, g. defines the maximum number of characters a field can contain
  3. Data type, c. specifies the kind of data a field can contain and how the field is used
  4. Primary key, b. field that uniquely identifies each record in a file
  5. Query language, j. consists of simple, English-like statements that allow users to specify the data to display, print, or store
  6. Log, a. listing of activities that modify the contents of a database
  7. Recovery utility, i. uses the logs and/or backups to restore a database when it becomes
    damaged or destroyed
  8. GIS, d. database that stores maps and other geographic data
  9. Data modeler, h. person who focuses on the meaning and usage of data
  10. Database administrator, f. creates and maintains the data dictionary, manages security of the database, monitors the performance of the database, and checks backup and recovery procedures

Short Answer

  1. – What is validation?
    Validation is the process of comparing data with a set of rules or values to find out if the data is correct.
    What are five types of validity checks?
    Five types of validity checks are alphabetic checks, numeric checks, range checks, consistency checks, and completeness checks.
  2. Why is data redundancy a weakness of file processing systems?
    Data redundancy a weakness of file processing systems because data redundancy means same information is duplicated in several files. This makes data redundancy.
    – Why is isolated data a weakness of file processing systems?
    Isolated data a weakness of file processing systems because data are scattered in various files, and the files may be in different format, writing new application program to retrieve data is difficult
  3. What is the database approach?
    Database approach is a approach whereby a pool of related data is shared by multiple application programs; offers significant advantages over traditional file-based approach
    – Describe five strengths of the database approach.
    Reduced Data Redundancy — Most data items are stored in only one file, which greatly reduces duplicate data. Improved Data Integrity — When users modify data in the database, they make changes to one file instead of multiple files. Shared Data — The data in a database environment belongs to and is shared, usually over a network, by the entire organization. Easier Access — The database approach allows nontechnical users to access and maintain data, providing they have the necessary privileges. Reduced Development Time — It often is easier and faster to develop programs that use the database approach.
  4. Describe how you might use a Simple Query Wizard.
    I might use a Simple Query Wizard for a query that searches for and lists students in an unversity.
    – What is query by example?
    Query by Example (QBE) is a database query language that has a graphical user interface to assist users with retrieving data.
  5. What are the advantages of object-oriented databases?
    Object-oriented databases have several advantages : they can store more types of data, access this data faster, and allow programmers to reuse objects.
    – Describe four examples of object-oriented databases.
    A multimedia database stores images, audio clips, and/or video clips. A groupware database stores documents such as schedules, calendars, manuals, memos, and reports. A computer-aided design (CAD) database stores data about engineering, architectural, and scientific designs. A hypertext database contains text links to other types of documents.
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