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Elm04_01 - Chapter 1 Databases and Database Users 1 CHAPTER...

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Chapter 1: Databases and Database Users CHAPTER 1: DATABASES AND DATABASE USERS Answers to Selected Exercises 1.7 Give some informal queries and updates that you would expect to apply to the database shown in Figure 1.2. Answer: (a) (Query) List the names of all students majoring in Computer Science. (b) (Query) What are the prerequisites of the Database course?. (c) (Query) Retrieve the transcript of Smith. This is a list of <CourseName, SectionIdentifier, Semester, Year, Grade> for each course section that Smith has completed. (d) (Update) Insert a new student in the database whose Name=Jackson, StudentNumber=23, Class=1 (freshman), and Major=MATH. (e) (Update) Change the grade that Smith received in Intro to Computer Science section 119 to B. 1. 8 What is the difference between controlled and uncontrolled redundancy? Answer: Redundancy is when the same fact is stored multiple times in several places in a database. For example, in Figure 1.5(a) the fact that the name of the student with StudentNumber=8 is Brown is stored multiple times. Redundancy is controlled when the
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