Databases Reference
In-Depth Information
9. Give an example of and describe an application that
would require sequential access in:
a. The university environment.
b. The insurance company environment.
c. The furniture store environment.
10. Give an example of and describe an application that
would require direct access in:
a. The university environment.
b. The insurance company environment.
c. The furniture store environment.
11. Should data be considered a true corporate resource?
Why or why not? Compare and contrast data to other
corporate resources (capital, plant and equipment,
personnel, etc.) in terms of importance, intrinsic
value, and modes of use.
12. Defend or refute the following statement: ''Data is
the most important corporate resource because it
describes all of the others.''
13. What are the two kinds of data redundancy, and
what are the three types of problems that they cause
in the information systems environment?
14. What factors might lead to redundant data across
multiple files? Is the problem managerial or techni-
cal in nature?
15. Describe the apparent tradeoff between data redun-
dancy and data integration in simple linear files.
16. In your own words, describe the key quality of a
DBMS that sets it apart from other data handling
systems.
17. Do you think that the single-file redundancy problem
is more serious, less serious, or about the same as
the multifile redundancy problem? Why?
18. What are the two defining goals of a database
management system?
19. What expectation should there be for a database
management system with regard to handling multi-
ple relationships? Why?
20. What are the problems with the ''horizontal'' and
''vertical'' solutions to the handling of multiple
relationships as described in the chapter?
21. What expectation should there be for a database
management system with regard to handling data
control issues such as data security, backup and
recovery, and concurrency control? Why?
22. What would the alternative be if database man-
agement systems were not designed to handle data
control issues such as data security, backup and
recovery, and concurrency control?
23. What is data independence? Why is it desirable?
24. What expectation should there be for a database
management system with regard to data indepen-
dence? Why?
25. What are the four major DBMS approaches? Which
approaches are used the most and least today?
EXERCISES
1. Consider a hospital in which each doctor is
responsible for many patients while each patient
is cared for by just one doctor. Each doctor has a
unique employee number, name, telephone number,
and office number. Each patient has a unique patient
number, name, home address, and home telephone
number.
a. What
d. Merge these two files into one, in the style of
Figure 3.6. Does this create any problems with
the data? Explain.
2. The Dynamic Chemicals Corp. keeps track of its
customers and its orders. Customers typically have
several outstanding orders while each order was
generated by a single customer. Each customer has a
unique customer number, a customer name, address,
and telephone number. An order has a unique order
number, a date, and a total cost.
a. What
kind
of
relationship
is
there
between
doctors and patients?
b. Develop sample doctor and patient data and
construct two files in the style of Figure 3.5
in which to store your sample data.
c. Do any fields have to be added to one or the
other of the two files to record the relationship
between doctors and patients? Explain.
kind
of
relationship
is
there
between
customers and orders?
b. Develop sample customer and order data and
construct two files in the style of Figure 3.5 in
which to store your sample data.
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