Assignment 3 Duplication and Redundancy for MIS208 Data Analysis

MIS208 Data Analysis

Assignment 3 Duplicated and Redundant Data

Set: 21 March 2014                 Due: 28 March 2014

Duplicated and Redundant Data

TeacherCourse

	teacherNo	teacherName	courseTaught	courseName
	P111	Susan	ENGL101	English 1
	P221	Adam	ENGL101	English 1
	P223	Ben	ENGL101	English 1
	P227	Milly	ENGL101	English 1
	P300	Tom	ENGL101	English 1
	P111	Susan	ENGL200	Translation
	P221	Adam	ENGL200	Translation
	E114	Tom	MATH107	Basic Maths I
	E222	Kevin	MATH107	Basic Maths I
	E114	Tom	MATH108	Basic Maths II

Figure 1

Q: Which attribute values are duplicated in the table Figure 1 above?

A: Same colour cells are repeated in the table Figure 1.

teacherNo	teacherName	courseTaught	courseName
P111	Susan	ENGL101	English 1
P221	Adam	ENGL101	English 1
P223	Ben	ENGL101	English 1
P227	Milly	ENGL101	English 1
P300	Tom	ENGL101	English 1
P111	Susan	ENGL200	Translation
P221	Adam	ENGL200	Translation
E114	Tom	MATH107	Basic Maths I
E222	Kevin	MATH107	Basic Maths I
E114	Tom	MATH108	Basic Maths II

Q: Which attribute values are redundant in the table in Figure 1?

A: I think, both teacherName and courseName values are unnecessary, because you can find teacherName with teacherNo and you can find courseName with courseNo. 

Q: Draw a diagram to show how redundancy can be eliminated by splitting the table into two or more pieces.

A: ideal database can be like the following.

informationTeachers

teacherNo	teacherName	teacherSurname
P111	Susan	Brown
P221	Adam	Smith
P223	Ben	Demon
P227	Milly	Obama
P300	Tom	Ronaldo
E114	Tom	Gates
E222	Kevin	Jelly
E114	Tom	Greedy

informationCourses

courseTaught	courseName
ENGL101	English1
ENGL200	Translation
MATH107	Basic Maths I
MATH108	Basic Maths II

TeacherCourse

teacherNo	courseTaught
P111	ENGL101
P221	ENGL101
P223	ENGL101
P227	ENGL101
P300	ENGL101
P111	ENGL200