Exercise Chapter 10 - Discovering Computer 2011 - Living in Digital World

Martin - 1601213690

01 PBT

True / False

1.   True
2.   True
3.   False
4.   True
5.   False
6.   False
7.   True
8.   True
9.   False
10. 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 fields )


Matching

1.   e
2.   g
3.   c
4.   b
5.   j
6.   a
7.   i
8.  d
9.   h
10. f


Short Answer

1. * Validation is the process of comparing data with a set of rules or values to find out if the data is correct.
    * Five types of validity checks are alphabetic checks, numeric checks, range checks, consistency checks, and completeness checks.

2. * Data redundancy a weakness of file processing systems because data redundancy means same information is duplicated in several files. This makes data redundancy.
    * 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. * 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.
    * 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 the faster to develop programs that use the database approach.

4. * Using a Simple Query Wizard for a query that searches for and lists students in an school or college.
    * Query By Example ( QBE ) is a database query language that has a graphical user interface to assist users with retrieving data.

5. * Object- oriented databases have several advantages, they can store more types of data, access data faster, and allow programmers to reuse objects.
    * 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.