Unit 5 : Relational Database ( Part 2 )

Question 1

List out the type of relational database （ 3 ）

Answer 1

1. 1 : M Relationship
   
   • 1 Course have many Class
2. 1 : 1 Relationship
   
   • Professor shares 1 Department
3. M : N Relationship

Question 2

Which relationship is rare in any relational database design?

Answer 2

1. 1 : 1 Relationship

Question 3

Which is the ideal relational modeling and should be the norm in any relational database design?

Answer 3

1. 1 : M Relationship

Question 4

What relationship cannot be implementel as such in the relational model?

Answer 4

1. M : N Relationship

Question 5

Which relationship is found in any database environment

Answer 5

1. 1 : M Relationship

Question 6

What is the relational database norm ?

Answer 6

1. 1 : M Relationship

Question 7

What relationship can M : N Relationships changed?

Answer 7

1. Change to two 1 : M Relationship

Question 8

What must contain in M : N Relationship?

Answer 8

1. Primary Keys

• Linking table contains multiple occurrences of the foreign key values

Question 9

What leads to data anomalies?

Answer 9

1. Data Redundancy

Question 10

What will be affected when data anamolies occured?

Answer 10

1. Destroy the effectiveness of the database

Question 11

What is crucial to exercising data redundancy control?

Answer 11

1. Foreign Keys

Question 12

What control data redundancies by using common attributes shared by tables

Answer 12

1. Foreign Keys

Question 13

What is necessary in some situations?

Answer 13

1. Data Redundancy

Question 14

What relationship means that entity components were not defined properly ?

Answer 14

1. 1 : 1 Relationship

Question 15

What relationship could indicate 2 entities actually belong in the same table ?

Answer 15

1. 1 : 1 Relationship

Question 16

What can avoid problems inherent to M:N relationships?

Answer 16

1. Creating a composite entity ( breaking into two 1:M relationships ) or bridge entity

Example on Notion

Question 17

What does composite entity table must contain?

Answer 17

1. At least the primary keys of original tables