Chapter 10

Discovering Computers 2011 : Living in a Digital World Answer

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
2. A
3. D
4. B
5. A
6. B
7. B
8. A

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 and faster to develop programs that use the database approach.

4. I might use a Simple Query Wizard for a query that searches for and lists students in an university.

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 this 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.