DCS5078 DATABASE SYSTEMS

TUTORIAL 1

CHAPTER 1
1. Discuss each of the following terms:
a. Data
b. Field
c. Record
d. File
2. What is data redundancy, and which characteristics of the file system can lead to it?
3. What is a DBMS, and what are its functions?
4. What is a business rule, and what is its purpose in data modeling?

Given the file structure shown in Figure T1.1, answer Problems 5 - 8.
FIGURE T1.1 The File Structure for Problems 5-8

5. How many records does the file contain, and how many fields are there per record?
6. What problem would you encounter if you wanted to produce a listing by city? How would you solve this problem by altering the file structure?
7. If you wanted to produce a listing of the file contents by last name, area code, city, state, or zip code, how would you alter the file structure?
8. What data redundancies do you detect, and how could these redundancies lead to anomalies? FIGURE T1.5 The File Structure for Problems 9-11

9. Identify and discuss the serious data redundancy problems exhibited by the file structure shown in Figure T1.5.

CDP OCT 2014/2015

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DCS5078 DATABASE SYSTEMS

TUTORIAL 1

10. Identify the different data sources in the file you examined in Problem 9.
11. Given your answer to Problem 10, what new files should you create to help eliminate the data redundancies found in the file shown in Figure T1.5?

Use the contents of Figure T1.11 to work problems 12.
FIGURE T1.11 Linking Relational Tables
Database name: Ch02_InsureCo

Table name: AGENT (first s ix attributes)

Link through AGENT_CODE

Table name: CUSTOMER

12. Write the business rule(s) that governs the relationship between AGENT and
CUSTOMER.
Using Figure T1.13 as your guide, work Problems 14. The DealCo relational diagram shows the initial entities and attributes for the DealCo stores, located in two