university of sunderland comm2q unit 2 comm2q lecture 2 his application building

University of Sunderland COMM2Q Unit 2

COMM2QCOMM2QLecture 2Lecture 2

HIS Application BuildingHIS Application Building


2

An Introduction toAn Introduction to

Relational Data Relational Data AnalysisAnalysis

(Normalisation)(Normalisation)


3

Steps in NormalisationSteps in Normalisation

1.1. Un-normalised formUn-normalised form

2.2. First Normal FormFirst Normal Form

3.3. Second Normal FormSecond Normal Form

4.4. Third Normal FormThird Normal Form

Relational Data AnalysisRelational Data Analysis


Relational Data AnalysisRelational Data AnalysisStudent Results TableStudent Results Table

CourseCode

CourseTitle

StudentCode

StudentName

Date ofBirth

TutorCode

TutorName

Grade Result

SYA SystemsAnalysis

A2345A7423B3472A3472B9843

SmithBarkerGreenHarrisGreen

20/08/6903/04/5923/02/7017/07/6910/11/68

17461746133017461330

JonesJonesJarvisJonesJarvis

ACDFB

Dist.PassPassFailMerit

COB COBOL A7423A4217B8238

BarkerMorrisCarter

03/04/6917/01/6809/12/69

152015201520

HooperHooperHooper

EBC

FailMeritPass

PAS Pascal A4217B9843A3393A4247

MorrisGreenWhiteCross

17/01/6810/11/6830/09/6925/12/69

1520128312831520

HooperTrotterTrotterHooper

ABEC

Dist.MeritFailPass



Possible Entities in SystemPossible Entities in System

• COURSECOURSE

• STUDENTSTUDENT

• TUTORTUTOR

• GRADE?GRADE?



Unnormalised Form:Unnormalised Form:

• Table made up of ROWS and Table made up of ROWS and COLUMNSCOLUMNS

• Rows grouped togetherRows grouped together

• Write table in unnormalised formWrite table in unnormalised form

• Choose unique KEY and underlineChoose unique KEY and underline



Data AttributesData Attributes• Student CodeStudent Code• Student NameStudent Name• Date of BirthDate of Birth

• All REPEAT for a given value of COURSE CODE

• Tutor CodeTutor Code• Tutor NameTutor Name• GradeGrade• ResultResult


8

UNF UNF 1NF 2NF 3NFLEVEL

Course Code 1Course Title 1

Student Code 2Student Name 2Date of Birth 2Tutor Code 2Tutor Name 2Grade 2Result 2


Normalisation TableNormalisation Table


9

• Any relation is in First Normal Form Any relation is in First Normal Form when it contains no repeating groups when it contains no repeating groups of dataof data


First Normal FormFirst Normal Form


10

UNF UNF 1NF 2NF 3NFLEVEL

Course Code 1 Course Code Course Title 1 Course Title

Student Code 2Student Name 2 Course CodeDate of Birth 2 Student CodeTutor Code 2 Student NameTutor Name 2 Date of BirthGrade 2 Tutor CodeResult 2 Tutor Name

GradeResult




11

Relational Data AnalysisRelational Data AnalysisNormalisation TableNormalisation Table

UNF UNF 1NF2NF 3NF LEVEL

Course Code 1 Course CodeCourse Title 1 Course Title

Student Code 2Student Name 2Date of Birth 2Tutor Code 2 Course CodeTutor Name 2 Student CodeGrade 2 Student NameResult 2 Date of Birth

Tutor CodeTutor NameGradeResult


12



UNF UNF 1NF 2NF3NF

LEVEL





13



UNF UNF 1NF 2NF3NF

LEVEL





14

• Any relation already in 1NF is also in Any relation already in 1NF is also in 2NF if EITHER the key is a single 2NF if EITHER the key is a single attribute OR the non-key items are attribute OR the non-key items are fully dependent on the WHOLE keyfully dependent on the WHOLE key

• In Second Normal Form, you remove In Second Normal Form, you remove data items which depend on only data items which depend on only part of a keypart of a key


Second Normal FormSecond Normal Form



Student CodeStudent Code Student NameStudent Name

Student CodeStudent Code

Tutor CodeTutor Code

Course CodeCourse Code



Student Name

Date of Birth

Course Code Tutor Code

Student Code Tutor Name

Grade

Result


17

UNF UNF 1NF2NF 3NF LEVEL

Course Code 1 Course Code Course CodeCourse Title 1 Course Title Course Title

Student Code 2Student Name 2 Course Code Course

CodeDate of Birth 2 Student Code

Student CodeTutor Code 2 Student Name Tutor CodeTutor Name 2 Date of Birth

Tutor NameGrade 2 Tutor Code GradeResult 2 Tutor Name Result

GradeResult

Student CodeStudent

NameDate of

Birth


Normalisation Table - 2NFNormalisation Table - 2NF


18

• Any relation in 2NF is also 3NF if all Any relation in 2NF is also 3NF if all non-key attributes are independent non-key attributes are independent of all other non-key attributes and all of all other non-key attributes and all key attributes are independent of all key attributes are independent of all the other key attributesthe other key attributes

• In Third Normal Form, you remove In Third Normal Form, you remove any attributes which are not directly any attributes which are not directly dependentdependent upon the keyupon the key


Third Normal FormThird Normal Form


19

UNF UNF 1NF 2NF3NF

LEVEL

Course Code 1 Course Code Course CodeCourse Code

Course Title 1 Course Title Course TitleCourse Title

Student Code 2Student Name 2 Course Code Course Code

Course CodeDate of Birth 2 Student Code Student

Code Student CodeTutor Code 2 Student Name Tutor Code

Tutor CodeTutor Name 2 Date of Birth Tutor

Name GradeGrade 2 Tutor Code Grade

Result 2 Tutor Name ResultStudent Code

GradeStudent Name

Result Student Code Date of Birth

Student NameDate of Birth

Tutor Code

Tutor Name

Grade

Result

Relational Data AnalysisRelational Data AnalysisNormalisation Table - 3NFNormalisation Table - 3NF


20

UNF UNF 1NF2NF 3NF

LEVEL






*Tutor CodeTutor Name 2 Date of Birth Tutor

Name *GradeGrade 2 Tutor Code Grade


GradeStudent Name

Result Student CodeDate of Birth


Tutor Code

Tutor Name

Grade

Result

Relational Data AnalysisRelational Data AnalysisNormalisation Table - 3NF

Foreign key



Summary:Summary:• Choose a suitable key from a table of raw dataChoose a suitable key from a table of raw data• Identify repeating groupsIdentify repeating groups• Write the data in unnormalised formWrite the data in unnormalised form• Convert unnormalised data to first normal formConvert unnormalised data to first normal form• Convert first normal form to second normal Convert first normal form to second normal

formform• Convert second normal form to third normal Convert second normal form to third normal

formform


NormalisationNormalisation

Constructing a Data Model from 3NF


UNF UNF 1NF2NF 3NF

LEVEL






*Tutor CodeTutor Name 2 Date of Birth Tutor

Name *GradeGrade 2 Tutor Code Grade


GradeStudent Name

Result Student CodeDate of Birth


Tutor Code

Tutor Name

Grade

Result

Normalisation Table - 3NF

Foreign key


Student Results Student Results RelationsRelations

COURSE

Course CodeCourse Title

COURSE-STUDENT

Course CodeStudent CodeTutor CodeGrade

STUDENT

Student CodeStudent NameDate of Birth

TUTOR

Tutor CodeTutor Name

GRADE

GradeResult


Create an entity type for each data relation e.g.

COURSE

Course Code

COURSE-STUDENT

Course CodeStudent Code*Tutor Code*Grade


Make compound key relations into details

refers to master / detail relationshipCOURSE STUDENT

COURSE-STUDENT

Course CodeStudent Code

Course Code Student Code


Make relations with foreign keys into detailsCOURSE STUDENT

COURSE-STUDENT



TUTOR GRADETutor Code Grade


Redrawn Entity ModelRedrawn Entity Model

COURSE STUDENT

COURSE-STUDENT



TUTOR GRADETutor Code Grade


Example 2Example 2

COURSE

Course CodeCourse Title

COURSE-STUDENT


STUDENT

Student CodeStudent Name

RESULT

Student Code(Course Code)(Ass. Number)Ass. Mark

ASSIGNMENT

(Course Code)(Ass. Number)Ass. Subject


Rule 1Rule 1

Create an entity type for each data relation e.g.

COURSE

Course Code

COURSE-STUDENT



Rule 2Rule 2Mark the qualifying elements of

hierarchic keys as a foreign key

• hierarchic key in this example

ASSIGNMENT

*(Course Code) (Ass. Number)

Rule 2

Note: ENTIRE key must be hierarchic


Rule 3Rule 3Check that all masters of compound

key relations are present

This example has two compound keys

• one made from simple key and hierarchic key

• one made from two simple keysCOURSE-STUDENT


RESULT

Student Code(Course Code)(Ass. Number)


Rule 4Rule 4


refers to master / detail relationshipCOURSE STUDENT

COURSE-STUDENT




Rule 4Rule 4


refers to master / detail relationship

COURSE STUDENT

COURSE-STUDENT



ASSIGNMENT

RESULT



Rule 4 Rule 4Rule 4


Rule 5Rule 5

COURSE

STUDENT

COURSE-STUDENTCourse Code

Student Code

Course Code

Student Code

ASSIGNMENT

RESULT



Make relations with foreign keys into details

Rule 5

Rule 2


3NF Model3NF Model

COURSE

STUDENT

COURSE-STUDENT


Course Code

Student Code

ASSIGNMENT

RESULT



Rule 4 Rule 4Rule 4

Rule 5

Rule 2

university of sunderland comm2q unit 2 comm2q lecture 2 his application building

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