Lecture 03 ERD to Relational

8/8/2019 Lecture 03 ERD to Relational

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Reducing E-R Diagrams to

Tables

Remedios de Dios Bulos


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EMPLOYEE

EID {PK}EName

ELastNameEFirstName

EMIEAddressEStNoEStNameECityECountry

EPhone [0..3]EGenderEBDate

EBYearEBMoEBDay

/EAge

DEPARTMENT

DNo {PK}DNameDLocation

1..* 1..10..*

0..*

friend1

friend2

WorksFor

Fr

ien

ds

0..1

1..* Support

PROJECT

PrNo {PK}PrNamePrLocation [1..*]

POSITION

PNo {PK}

PNameSalary

J

obI

s

1..*

0..1

1..10..1

Co

ntro

ls

0..1

1..*

MACHINE

MNo {PK}MDescMLocation

ERDCompanyDatabase

manager

staff

DEPENDENTS

DeGender

DeBDateDeBYearDeBMoDeBDay

Relationship

WorksOn

0..*

1..*

0..*

0..*

0..*

DeName

DeLastNameDeFirstNameDeMI

USE {R}

UseDateStart Time

SHourSMin

End TimeEHourEMin

/HoursPerDay

WorksOn {R}

HoursPerMonth

MANAGES {R}

MgrStartDate


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Objective : Logical Design

Design Relational Schema of a Company


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Relational Schema of Company Database

POSITION (PNo, PName, Salary)

MACHINE(MNo, MDesc, MLocation)

DEPENDENTS (EID,DeLastName,DeFirstName,DeMI, DeGender,DeBYear, DeBMo, DeBDay, Relationship)

DEPARTMENT (DNo, DName, DLocation, MgrEID, MgrStartDate)

EMPLOYEE (EID, ELastName, EFirstName, EMI, EStNo, EStName, ECity,ECountry, EGender, EBYear, EBMo, EBDay, EAge, DNo, PNo)

PROJECT (PrNo, PrName, DNo)

WorksOn (EID,PrNo, HoursPerMonth )

HasPhone (EID, EPhone )

ProjectLocation (PrNo, PrLocation )

USE ( EID,PrNo,MNo, UseDate, SHour, SMin, EHour, EMin, HoursPerDay )

Friends (EID1,EID2)


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EMPLOYEE

Field DataType

LengthRequired

Foreign Key

EID {PK} char 10 Not nullELastName

char 30 Not nullEFirstName char 30 Not nullEMI :PK char 4EStNo char 5EStName char 20ECity char 20 Not nullECountry char 20 Not nullEGender char 1 Not nullEBYear Date Not null

EBMo Date Not nullEBDay Date Not nullEAge intDNo char 5 Not null DEPARTME

NTPNochar 5

Not null POSITION


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DEPARTMENT

Field DataType

LengthRequired

Foreign Key

DNo {PK} char 10 Not nullDName char 50 Not nullDLocation char 50 Not nullMgrEID char 10 EMPLOYEEMgrStartDate Date

POSITION

Field Data

Type

LengthRequire

d

Foreign Key

PNo{PK} char 10 Not nullPName char 50 Not nullSalary money


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PROJECT

Field DataType

LengthRequired

Foreign Key

PrNo{PK} char 10 Not null

PrName char 50 Not nullDNo char 10 Not null DEPARTME

NTMACHINE

Field Data

Type

LengthRequire

d

Foreign Key

MNo{PK} char 10 not nullMDesc char 50 Not nullMLocation char 50 Not null


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DEPENDENTS

Field Data

Type

LengthRequire

d

Foreign Key

EID{PK} char 10 Not null EMPLOYEEDeLastName char 20 Not nullDeFirstName char 20 Not nullDeMI char 4DeGender char 1DeBYear dateDeBMo dateDeBDay dateRelationship char 50


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WorksOn

Field DataType

LengthRequired

Foreign Key

EID{PK} char 10 Not null EMPLOYEE

PrNo char 10 Not null PROJECTHoursPerMonth float

ProjectLocation

Field DataType LengthRequired Foreign KeyPrNo{PK} char 10 Not null PROJECTPrLocation char 50 Not null

FRIENDS

Field{PK}DataType

LengthRequired

Foreign KeyEID1 char 10 Nut null EMPLOYEEEID2 char 10 Nut null EMPLOYEE


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USE

Field DataType

LengthRequired

Foreign Key

EID{PK} char 10 Nut null EMPLOYEEPrNo

char 10 Nut null PROJECTMNo char 10 Nut null MACHINEUseDate dateSHour dateSMin dateEHour dateEMin dateHoursPerDay float

HasPhone

Field DataType

LengthRequired

Foreign Key

EID{PK} char 10 Not null EMPLOYEEEPhone char 10 Not null


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Step by Step Conversion

From ERD to Tables


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Tabular Representation of theER Diagram [EN2007]

STEP 1: For each regular (strong) entity type E in theER schema

create a relation R that includes all thesimple (and singlevalued) attributes of E.

include only the simple component attributes of acomposite attribute.

choose one of the key attributes of E as primary key forR.

if the chosen key of E is composite, the set of simpleattributes that form it will together from the primary keyof R.


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E(attribute-1, attribute-2, attribute-3-a, attribute-3-b, attribute-

5)

Step1- EDR To Relational: Strong Entity E

E

attribute-1{PK}attribute-2attribute-3

attribute-3-a

attribute-3-battribute-4 [0..*]/attribute-5

E

attribute-1

attribute-2

attribute-3-a

attribute-3-b

attribute-5

Primary

Key


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EMPLOYEE

EID {PK}EName

ELastNameEFirstNameEMI

EAddressEStNoEStNameECityECountry


EBYearEBMoEBDay

/EAge

DEPARTMENT


1..* 1..10..*

0..*

friend1

friend2

WorksFor

Fr

ien

ds

0..1

1..* Support

PROJECT


POSITION

PNo {PK}PNameSalary

J

obIs

1..*

0..1

1..10..1

Co

ntro

ls

0..1

1..*

MACHINE

MNo {PK}MDesc

MLocation

ERDCompanyDatabase

manager

staff

DEPENDENTS

DeGender


Relationship

WorksOn

0..*

1..*

0..*

0..*

0..*

DeNameDeLastNameDeFirstNameDeMI

USE {R}

UseDateStart Time

SHourSMin

End TimeEHourEMin

/HoursPerDay

WorksOn {R}

HoursPerMonth

MANAGES {R}

MgrStartDate


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EMPLOYEE

EID {PK}EName


EAddressEStNo

EStNameECityECountry


EBYearEBMoEBDay

/EAge

DEPARTMENT

DNo {PK}DName

DLocation

PROJECT


POSITION

PNo {PK}PNameSalary

MACHINE

MNo {PK}MDesc

MLocation

DEPENDENTS{W}

DeName {PK}DeLastNameDeFirstNameDeMI

DeGenderDeBDate

DeBYearDeBMoDeBDay

Relationship

Strong Entity

Strong Entity

Strong EntityStrong Entity

Strong Entity

Weak Entity

Which are strong or weak entities? : Company


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Step-1 EDR To Relational: Strong Entity

EMPLOYEE

EID {PK}EName


EAddressEStNoEStNameECity

ECountryEPhone [0..3]EGenderEBDate

EBYearEBMoEBDay

/EAge

EMPLOYEE (EID, ELastName, EFirstName, EMI, EStNo, EStName,ECity, ECountry, EGender, EBYear, EBMo, EBDay, EAge)

COMPANY

PK


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COMPANY

DEPARTMENT

DNo {PK}DName

DLocation

POSITION

PNo {PK}PNameSalary

POSITION

PNo PNameSalary


DEPARTMENT

DNo DNam

e

DLocatio

n

DEPARTMENT (DNo, DName, DLocation)


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COMPANY

PROJECT


MACHINE


PROJECT

PrNo PrName

PROJECT (PrNo, PrName)

MACHINE

MNo MDescMLocatio

n



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EDR To Relational: Company

After Step-1, we have the following relations:

EMPLOYEE (EID, ELastName, EFirstName, EMI, EStNo, EStName,ECity, ECountry, EGender, EBYear, EBMo, EBDay, EAge)






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STEP 2: For each weak entity type Win the ER schema withowner entity type E,

create a relation R and include allsimple (and single valued)attributes of W as attributes of R.

include as foreign key attributesofR theprimary keyattributes(s) of the relation(s) that correspond to the ownerentity type(s). This handles the identifying relationship typeof W.

Theprimary key of R is the combination of theprimary key(s)of the owner(s) and thepartial key of the weak entity typeW, if there are any.



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W(attribute-a, attribute-1, attribute-2, attribute-3-1, attribute-3-2, attribute-

5)

Step2- EDR To Relational: Weak Entity W

E2 {W}attribute-2

attribute-3attribute-3-1attribute-3-2

attribute-4 [0..*]

/attribute-5

W

attribute-1

attribute-2

attribute-3-1

attribute-3-2

attribute-5

PrimaryKey

E1attribute-a{PK}

attribute-battribute-c

attribute-a

ForeignKey

attribute-1


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EMPLOYEE

EID {PK}EName


EAddressEStNo



EBYearEBMoEBDay

/EAge

DEPARTMENT

DNo {PK}DName

DLocation

PROJECT


POSITION

PNo {PK}PNameSalary

MACHINE

MNo {PK}MDesc

MLocation

DEPENDENTS{W}

DeName {pk}DeLastNameDeFirstNameDeMI

DeGenderDeBDate

DeBYearDeBMoDeBDay

Relationship

Strong Entity

Strong Entity

Strong EntityStrong Entity

Strong Entity

Weak Entity

Which are strong or weak entities? : Company


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EMPLOYEE

EID {PK}EName




EBYearEBMoEBDay

/EAge

DEPARTMENT


1..* 1..10..*

0..*

friend1

friend2

WorksFor

Fr

ien

ds

0..1

1..* Support

PROJECT


POSITION

PNo {PK}PNameSalary

Job

Is

1..

*

0..1

1..10..1

Co

ntr

ols

0..1

1..*

MACHINE

MNo {PK}MDesc

MLocation

ERDCompanyDatabase

manager

staff

DEPENDENTS

DeGender


Relationship

WorksOn

0..*

1..*

0..*

0..*

0..*


USE {R}

UseDateStart Time

SHourSMin

End TimeEHourEMin

/HoursPerDay

WorksOn {R}

HoursPerMonth

MANAGES {R}

MgrStartDate


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Step-1 EDR To Relational: Weak Entity

COMPANY

DEPENDENTS (EID,DeLastName,DeFirstName,DeMI, DeGender, DeBYear, DeBMo,

DeBday, Relationship)

DEPENDENTS{W}

DeGender


Relationship

DEPENDENTSDeLastName DeFirstName DeMI DeGender DeBYear DeBMo DeBDay Relationship

EMPLOYEE

EID {PK}EName




EBYearEBMoEBDay

/EAge

EID



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EDR To Relational:COMPANY


EMPLOYEE (EID, ELastName, EFirstName, EMI, EStNo, EStName, ECity,ECountry, EGender, EBYear, EBMo, EBDay, EAge)





DEPENDENTS (EID,DeLastName, DeFirstName,DeMI, DeGender,DeBYear, DeBMo, DeBDay, Relationship)


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STEP 3: For each binary 1:1 relationship type R in theER schema, identify the relationsS and Tthatcorrespond to the entity typesparticipating in R.

Choose an entity type with total participation (if there are any)

in R in the role of S; the other entity will play the role of T; Include asforeign key in Stheprimary key of T.

Include all the simple (and single-valued) attributes of thebinary 1:1 relationship type R as attributes of S.


NOTE: For binary 1:1 relationship type:no new relation is createdthe entity that plays the role of S is modified


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E1(attribute-a, attribute-b, attribute-c, attribute-1)

Step 3- EDR To Relational: Binary 1:1

E2


E1

attribute-a attribute-b attribute-c

PrimaryKey

E1

attribute-a{PK}attribute-battribute-c

1..1 0..1

R

ST Foreign

Key

attribute-1

E1(attribute-a, attribute-b, attribute-c)

CASE 1


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E2


E1


PrimaryKey

E1


1..1 1..1

R

ST Foreign

Key

attribute-1


CASE 2-A


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E1-E2(attribute-a, attribute-b, attribute-c, attribute-1,attribute-2, attribute-

3}


E2


E2

attribute-1 attribute-2 attribute-3

E1


1..1 1..1

R

CASE 2-B

E1


E1-E2attribute-a attribute-b attribute-c attribute-1 attribute-2 attribute-3


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E1(attribute-a, attribute-b, attribute-c, attribute-1, attribute-r1, attribute-r2)


E2


E1


PrimaryKey

E1


1..1 0..1

ST Foreign

Key

attribute-1 attribute-r1 attribute-r2


Rattribute-r1

attribute-r2

CASE 3

EMPLOYEE 1 *f i d1


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EMPLOYEE

EID {PK}EName




EBYearEBMoEBDay

/EAge

DEPARTMENT


1..* 1..10..*

0..*

friend1

friend2

WorksFor

Fr

ien

ds

0..1

1..* Support

PROJECT


POSITION

PNo {PK}PName

Salary

Job

Is

1..

*

0..1

1..10..1

Co

ntr

ols

0..1

1..*

MACHINE

MNo {PK}MDesc

MLocation

ERDCompanyDatabase

manager

staff

DEPENDENTS

DeGender


Relationship

WorksOn

0..*

1..*

0..*

0..*

0..*


USE {R}

UseDateStart Time

SHourSMin

End TimeEHourEMin

/HoursPerDay

WorksOn {R}

HoursPerMonth

MANAGES {R}

MgrStartDate


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EMPLOYEEEID {PK}EName


EAddressEStNo



EBYearEBMoEBDay

/EAge

DEPARTMENT


Step-3 EDR To Relational - Binary 1:1 Company

1..10..1

MANAGES {R}

MgrStartDate

managerS

TDEPARTMENTDNo DNam

eDLocation


MgrEIDMgrStartDate

DEPARTMENT (DNo, DName, Dlocation, MgrEID, MgrStartDate)


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STEP 4: For each regular (non-weak) binary 1:* (1:N)relationship type R,

identify the relation S that represents the participating entitytype at the N-side of the relationship type.

Include as foreign key in S the primary key of the relation Tthat represents the other entity type participating in R.

Include any simple (and single-valued) attributes of the 1:Nrelationship type as attributes of S.



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Step 4- EDR To Relational: Binary 1:*

E2


E1


PrimaryKey

E1


1..* 0..1

R

ST Foreign

Key

attribute-1


Case 1


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E1(attribute-a, attribute-b, attribute-c, attribute-1, attribute-r1, attribute-r2)

Step 4- EDR To Relational: Binary 1:*

E2


E1


PrimaryKey

E1


1..* 0..1

ST Foreign

Key

attribute-1 attribute-r1 attribute-r2


Rattribute-r1

attribute-r2

CASE 2

EMPLOYEE 1 * 1 1friend1


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EMPLOYEE

EID {PK}EName




EBYearEBMoEBDay

/EAge

DEPARTMENT


1..* 1..10..*

0..*

friend1

friend2

WorksFor

Fr

ien

ds

0..1

1..* Support

PROJECT


POSITION

PNo {PK}PName

Salary

JobIs

1..

*

0..1

1..10..1

Co

ntr

ols

0..1

1..*

MACHINE

MNo {PK}MDesc

MLocation

ERDCompanyDatabase

manager

staff

DEPENDENTS

DeGender


Relationship

WorksOn

0..*

1..*

0..*

0..*

0..*

DeNameDeLastName

DeFirstNameDeMI

USE {R}

UseDateStart Time

SHourSMin

End TimeEHourEMin

/HoursPerDay

WorksOn {R}

HoursPerMonth

MANAGES {R}

MgrStartDate

St 4 EDR T R l ti l Bi 1 * C


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EMPLOYEE

EID {PK}

ENameELastNameEFirstNameEMI

EAddressEStNoEStNameECity

ECountryEPhone [0..3]EGenderEBDate

EBYearEBMoEBDay

/EAge

DEPARTMENT


1..* 1..1

WorksFor

PROJECT


POSITION

PNo {PK}PNameSalaryJobIs

1..* 0..1

Co

ntr

ols

0..1

1..*

staff

S T

S

T

TS

EMPLOYEE (EID, ELastName, EFirstName, EMI,EStNo, EStName, ECity, ECountry, EGender, EBYear,EBMo, EBDay, EAge)


Relations to be modified:

Step-4 EDR To Relational - Binary 1:* Company



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EMPLOYEE

EID {PK}

ENameELastNameEFirstNameEMI



EBYearEBMoEBDay

/EAge

DEPARTMENT

DNo {PK}

DNameDLocation

1..* 1..1

WorksFor

POSITION

PNo {PK}PNameSalary

JobIs

1..* 0..1

staff

S T

TS

EMPLOYEE (EID, ELastName, EFirstName,EMI, EStNo, EStName, ECity, ECountry,EGender, EBYear, EBMo, EBDay, EAge)

EMPLOYEE (EID, ELastName, EFirstName, EMI, EStNo,EStName, ECity, ECountry, EGender, EBYear, EBMo, EBDay,

EAge, DNo, PNo)


PK

FK



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DEPARTMENT


PROJECT


Co

ntr

ols

0..1

1..*

S

T




EDR T R l ti l COMPANY


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EMPLOYEE (EID, ELastName, EFirstName, EMI, EStNo, EStName, ECity,

ECountry, EGender, EBYear, EBMo, EBDay, EAge)



MACHINE(MNo, MDesc, MLocation)DEPENDENTS (EID,DeLastName,DeFirstName,DeMI, DeGender,DeBYear, DeBMo, DeBDay, Relationship)





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STEP 5: For each binary *:* (M:N) relationshiptype R,

create a new relation Sto represent R.

Include as foreign key attributes in S the primary keysof the relations that represent the participatingentity types; their combination will form the

primary key of S.

Also include any simple attributes of the M:Nrelationship (or simple components of compositeattributes) as attributes of S.



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R(attribute-a, attribute-1)

Step 5- EDR To Relational: Binary *:*

E2


R

attribute-a attribute1

PrimaryKey

E1


1..* 0..*

R

ForeignKey

Case 1

Create a new relation

Step 5- EDR To Relational: Binary *:*


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R(att-a, att-1, att-r1, att-r2)

Step 5 EDR To Relational: Binary :

E2

att-1{PK}att-2att-3

R

att-a att-1 att-r1 att-r2

PrimaryKey

E1

att-a{PK}att-batt-c

1..* 0..*

ForeignKey

Case 2


Ratt-r1att-r2

EMPLOYEE DEPARTMENT1 * 1 1friend1


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EMPLOYEE

EID {PK}EName




EBYearEBMoEBDay

/EAge

DEPARTMENT


1.. 1..10..*

0..*

friend1

friend2

WorksFor

Fr

ien

ds

0..1

1..* Support

PROJECT


POSITION

PNo {PK}PName

Salary

Jo

bIs

1..

*

0..1

1..10..1

Co

ntr

ols

0..1

1..*

MACHINE

MNo {PK}MDesc

MLocation

ERDCompanyDatabase

manager

staff

DEPENDENTS

DeGender


Relationship

WorksOn

0..*

1..*

0..*

0..*

0..*

DeNameDeLastName

DeFirstNameDeMI

USE {R}

UseDateStart Time

SHourSMin

End TimeEHourEMin

/HoursPerDay

WorksOn {R}

HoursPerMonth

MANAGES {R}

MgrStartDate

Step 5 EDR To Relational Binary *:* Company


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EMPLOYEE

EID {PK}EName




EBYearEBMoEBDay

/EAge

0..*

0..*

friend1

friend2

Fr

ien

ds

PROJECT


WorksOn {R}

HoursPerMonth0..*

1..*

Step-5 EDR To Relational - Binary *:* Company

New Relations To be Created:WorksOnFriends


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Step 5 EDR To Relational Binary *:* Company


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EMPLOYEE

EID {PK}EName




EBYearEBMoEBDay

/EAge

0..*

0..*

friend1

friend2

Fr

ien

ds

Step-5 EDR To Relational - Binary *:* Company

Friends (EID1,EID2)

Friends

EID1 EID2

PK



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FRIENDS (EID1,EID2)


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STEP 6: For each multi-valued attribute A,

create a new relation Rthat includes an attributecorresponding to A.

Include the primary key attribute K (as a foreign keyin R) of the relation that represents the entity typeor relationship type that has A as an attribute.

The primary key of R is the combination of A and K.

If the multi-valued attribute is composite, includeits simple components.


St 6 EDR T R l ti l Bi M lti l d


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R(attribute-a, attribute-1)

Step 6- EDR To Relational: Binary Multi-valued

R

attribute-a attribute1

PrimaryKey

E1

attribute-a{PK}attribute-battribute-c [1..*]

ForeignKey


Case1: multi-valued attributeis a simple attribute

St 6 EDR T R l ti l Bi M lti l d


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R(att-a, att-1, att-c-2 att-c-3)

Step 6- EDR To Relational: Binary Multi-valued

R

att-a att-c-1 att-c-2 att-c-3

PrimaryKey

E1att-a{PK}

att-batt-c [1..*]

att-c-1 {pk}att-c-2

att-c-3

ForeignKey


Case2: multi-valued attributeis a composite attribute

discriminator

EMPLOYEE DEPARTMENT1..* 1..1friend1


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EID {PK}EName




EBYearEBMoEBDay

/EAge

DEPARTMENT


1..10..*

0..*

friend2

WorksFor

Fr

ien

ds

0..1

1..* Support

PROJECT


POSITION

PNo {PK}PName

Salary

Jo

bIs

1..

*

0..1

1..10..1

Co

ntr

ols

0..1

1..*

MACHINE

MNo {PK}MDesc

MLocation

ERDCompanyDatabase

manager

staff

DEPENDENTS

DeGender


Relationship

WorksOn

0..*

1..*

0..*

0..*

0..*

DeNameDeLastName

DeFirstNameDeMI

USE {R}

UseDateStart Time

SHourSMin

End TimeEHourEMin

/HoursPerDay

WorksOn {R}

HoursPerMonth

MANAGES {R}

MgrStartDate

Step-6 EDR To Relational - Multi-valued Attribute


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EMPLOYEE

EID {PK}EName




EBYear

EBMoEBDay

/EAge

PROJECT


Step-6 EDR To Relational - Multi-valued Attribute

Create New Relations:HasPhone

ProjectLocation

HasPhone

EID EPhone


Project LocationPrNo PrLocatio

n




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FRIENDS (EID1,EID2)



Tabular Representation of the ER Diagram [EN2007]


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STEP 7: For each n-ary relationship type R, n>2:

create a new relation Sto represent R.

Include as foreign key attributes in S the primary keys of therelations that represent the participating entity types.

Also, include any simple attributes of the n-aryrelationshiptype (or simple components of composite attributes) as

attributes of S.

Theprimary key of S is usually a combination of all theforeign keys that reference the relations representing theparticipating entity types.

However if the cardinality constraints on any one of the entitytypes E participating inR is1, then the primary key of S

should not include the foreign key attribute that referencesthe relation E corresponding to E.

Tabular Representation of the ER Diagram [EN2007]

Step 7 EDR To Relational: Multi way (Cases)


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S(attribute-a, attribute-1, attribute-i)

Step 7- EDR To Relational: Multi-way (Cases)

E2

attribute-1{PK}attribute-2

E1

attribute-a{PK}attribute-b

0..* R

E3

attribute-i{PK}attribute-ii

1..*

0..*

Create a new relation S

Step 7 EDR To Relational: Multi way (Cases)


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S(attribute-a, attribute-1, attribute-i, attribute-r1,attribute-r2)

Step 7- EDR To Relational: Multi-way (Cases)

E2


E1


0..*

E3


1..*

0..*


R {R}

attribute-r1attribute-r2

PK


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Step-7 EDR To Relational - Multi-way: Company


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EMPLOYEE

EID {PK}EName




EBYearEBMoEBDay

/EAge

PROJECT

PrNo {PK}PrNamePrLocation [1..*]USE {R}

UseDateStart Time

SHourSMin

End TimeEHourEMin

/HoursPerDay

MACHINE


0..*

0..*

0..*

p y p y

New Relation to be created:USE

USE

EID PrNo MNoUseDate

SHour SMin EHourEMin HoursPerDay

USE ( EID,PrNo,Mno, UseDate, Shour, Smin, Ehour, Emin, HoursPerDay )



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FRIENDS (EID,EID2)



USE ( EID,PrNo,Mno, UseDate, SHour, SMin, EHour, EMin, HoursPerDay )

EMPLOYEE


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Field DataType

LengthRequired

Foreign KeyEID char 10 Not nullELastName char 30 Not nullEFirstName char 30 Not nullEMI char 4EStNo char 5EStName char 20

ECity char 20 Not nullECountry char 20 Not nullEGender char 1 Not nullEBYear Date Not nullEBMo

Date Not nullEBDay Date Not nullEAge intDNo char 5 Not null DEPARTME

NTPNo char 5 Not null POSITION

DEPARTMENT


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DEPARTMENT

Field DataType

LengthRequired

Foreign KeyDNo char 10 Not null

DName char 50 Not nullDLocation char 50 Not nullMgrEID char 10 EMPLOYEEMgrStartDate Date

POSITION

Field DataType

LengthRequired

Foreign KeyPNo char 10 Not nullPName char 50 Not nullSalary money

PROJECT


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PROJECT

Field DataType

LengthRequired

Foreign KeyPrNo char 10 Not nullPrName

char 50 Not nullDNo char 10 Not null DEPARTMENT

MACHINE

Field Data

Type

LengthRequire

d

Foreign Key

MNo char 10 not nullMDesc char 50 Not nullMLocation char 50 Not null


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DEPENDENTS

Field DataType

LengthRequired

Foreign KeyEID char 10 Not null EMPLOYEEDeLastName char 20 Not nullDeFirstName char 20 Not nullDeMI char 4DeGender char 1

DeBYear dateDeBMo dateDeBDay dateRelationship char 50

WorksOn


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Field DataType

LengthRequired

Foreign KeyEID char 10 Not null EMPLOYEEPrNo

char 10 Not null PROJECTHoursPerMonth float

ProjectLocation

Field Data

Type

LengthRequire

d

Foreign KeyPrNo char 10 Not null PROJECTPrLocation char 50 Not null

FRIENDS

Field DataType

LengthRequired

Foreign KeyEID1 char 10 Nut null EMPLOYEEEID2 char 10 Nut null EMPLOYEE

USE


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Field DataType

LengthRequired

Foreign KeyEID char 10 Nut null EMPLOYEEPrNo char 10 Nut null PROJECTMNo char 10 Nut null MACHINEUseDate dateSHour dateSMin date

EHour dateEMin dateHoursPerDay float

HasPhone

Field DataType

LengthRequired

Foreign KeyEID char 10 Not null EMPLOYEEEPhone char 10 Not null


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Exercises

Exercise #1 : Reduce to Relations (Tables)


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STUDENT

SID {PK}

SNameSDegreeSGPA

FACULTY

FID {PK}FNameFDegree

DNo

COURSE

CCode {PK}CNameCDesc

CUnits

ENROLL {R}

SectionRoomNo

SkedDayStartTimeEndTime

Grade

0..* 1..*

1..*



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STUDENT

SID {PK}SNameSDegreeSGPA

FACULTY

FID {PK}FNameFDegreeDNo

COURSE

CCode {PK}CName

CDescCUnits

CLASS {W}

Sec {PK}

RoomNoSked

DayStartTimeEndTime

0..*1..*

1..*

ENROLL {R}

Grade

O

fferin

g

0..1

1..*

Sec {PK}



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SUPPLIER

SName {PK}SAddress

PROJECT

ProjName {PK}ProjDesc

ProjLeader

PART

PartNo {PK}PartDesc

SUPPLY {W}

Quantity

0..1

0..1

0..1

No partial key

1..*1..*

1..*

S-S S-Proj

S-P

ar

t

HOW??Convert therelationship supply to aweak entity



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SUPPLIER

SName {PK}SAddress

PROJECT

ProjName {PK}ProjDesc

ProjLeader

PART

PartNo {PK}PartDesc

SUPPLY

SupplyNo {PK}Quantity

0..1 0..1

0..1 Primary Key(surrogate key)

1..*1..*

1..*

S-S S-Proj

S-P

ar

t

HOW??Convert the relationshipsupply to a Strong entityand add an artificial orsurrogate key

LOAN-TRAN {W}Exercise #5 : Reduce to Relations (Tables)


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BANK

BkCode {PK}

BkName

BkAddress

ACCT-TRAN{W}AT-Date

AT-Type

AT-Amount

BRANCH {W}

BrAddress

ACCOUNT

AcctNo {PK}

Balance

AcctType

LOAN

LoanNo {PK}

Amount

LoanTypeCUSTOMER

SSN {PK}

CName

CAddress

CPhone

1..1

1..*

BkHasBr

0..1

1..*

Br-Offer-A

cct

0..1

1..*

Br-Offer-A

cct

1..*

0..*

1..*

0..*Cust-Acct

Cust-Loan

LT-Date

LT-Type

LT-Amount

Do-AT

Do

-LT

1..*

1..1

1..*

1..1

LT-No

AT-No

BrNo



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D

d1{PK}

d2

d3

d4

A

a1{PK}

a2

a3

B

b1{PK}

b2b3

C

c1{PK}

c2c3 [1..*]

c4{d/pk}c5

c6

E {W}

e2

/e3

F

f1{PK}

f2f3

f4R1{R}

r1-1

r1-2

R2{R}

r2-1[1..*]r2-2

{d}r2-3r2-4

R3{R}

r3-1

r3-2

e1

G

g1{PK}

g2

H {W}

h1

h2

I

i1 {PK}

i2

J

j1{PK}

j2

R4{R}

r4-1

r4-2

R5

R6

R7

R8

R10

R9

0 ..*

0..*1..1 1..1

1..*

1..* 1..*

0..1

0..1 0..1

0..1

1..*

1..1

1..*

1..1

0..*

1..*

0..1

1..1

1..1

1..* 0..*


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75

END Thank You!!

MS ACCESS DATA TYPES


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Data type Storage size DescriptionBINARY 1 byte per

character

Any type of data may be stored

in a field of this type. Notranslation of the data (forexample, to text) is made. Howthe data is input in a binaryfield dictates how it will appear

as output.

BIT 1 byte Yes and No values and fieldsthat contain only one of twovalues.

TINYINT 1 byte An integer value between 0 and255.




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Data type Storage Size DescriptionMONEY 8 bytes A scaled integer

between 922,337,203,685,477.5808 and922,337,203,685,477.5807.

DATE 8 bytes A date or time valuebetween the years 100and 9999.

UNIQUEIDENTIFIER 128 bits A unique identificationnumber used withremote procedure calls.

S CC SS S



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Data type Storage size DescriptionREAL 4 bytes A single-precision floating-point valuewith a range of 3.402823E38 to

1.401298E-45 for negative values,1.401298E-45 to 3.402823E38 for positivevalues, and 0.

FLOAT 8 bytes A double-precision floating-point valuewith a range of 1.79769313486232E308to 4.94065645841247E-324 for negativevalues, 4.94065645841247E-324 to1.79769313486232E308 for positivevalues, and 0.

SMALLINT 2 bytes A short integer between 32,768 and32,767. (See Notes)

Data type Storage size Description

INTEGER 4 bytes A long integer between 2,147,483,648


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y g gand 2,147,483,647. (See Notes)DECIMAL 17 bytes An exact numeric data type that holdsvalues from 1028 - 1 through - 1028 - 1.You can define both precision (1 - 28)

and scale (0 - defined precision). Thedefault precision and scale are 18 and 0,respectively.

TEXT 2 bytes per

character

Zero to a maximum of 2.14 gigabytes.IMAGE As required Zero to a maximum of 2.14 gigabytes.

Used for OLE objects.CHARACTER2 bytes percharacter

Zero to 255 characters.

Source Type Target Type


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Source Type Target Type

Java Pre-Type Java Type Java Post-Type Data Element Type

boolean bit

byte tiny integershort small integer

int integerlong long binary

float floatdouble double precision

const char characterchar character varying

const char * long character

char * long textchar * long var character

default long var character

Step 7- EDR To Relational: Multi-way


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p y

E2


E1


0..* R

Case 1:

Cardinality -All ManyR has no attributes

E3


1..*

0..*




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p y

E2


E1


0..* R

Case 2:Mixture of many andone cardinalitiesR has no attributes

E3


1..*

0..1


Do not includein the primarykey (whose

cardinality isone); butinclude as aforeign key



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E2(attribute-1, attribute-2, attribute-a, attribute-i)

p y

E2


E1


0..1 R

E3


1..1

0..1

Modify relation E2 (with total participation)

Case 3:All one cardinalitiesMixture of total and

partialR has no attributes Foreign key



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E1(attribute-a, attribute-b, attribute-1, attribute-i)

p y

E2


E1


1..1 R

E3


1..1

1..1

Modify relation E1, E2 or E3 (with total participation)

Case 4-a:All one cardinalitiesAll total participationR has no attributes

Foreign key



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p y

E2


E1


1..1 R

E3


1..1

1..1

Case 4-b:All one cardinalitiesAll total participationR has no attributes

S(attribute-a, attribute-b, attribute-1, attribute-2, attribute-i,attribute-ii)

Drop relations E1, E2 and E3 and then create a new relation S



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E2


E1


0..*

E3


1..*

0..*


R {R}


Case 5:

Cardinality -All ManyR has attributes



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E2


E1


0..*

E3


1..*

0..1


R {R}


Case 6:Mixture of many andone cardinalitiesR has attributes

Do not includein the primarykey (whosecardinality isone); but

include asforeign key



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E1(attribute-a, attribute-b, attribute-1,attribute-i,attribute-r1,attribute-r2)

E2


E1


1..1

E3


1..1

0..1

Modify either E1 or E2 (with total participation)

R {R}


Case 7:All one cardinalitiesMixture of total and

partialR has attributes Foreign key



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E1(attribute-a, attribute-b, attribute-1, attribute-i,attribute-r1,attribute-r2)

E2


E1


1..1

E3


1..1

1..1

Modify any of relations E1, E2 and E3 (total participation)

R {R}


Case 8-a:All one cardinalitiesAll total participationR has attributes

Foreign key



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S(attribute-a, attribute-b, attribute-1, attribute-2, attribute-i,attribute-ii, attribute-r1,attribute-r2)

E2


E1


1..1

E3


1..1

1..1

Drop relations E1, E2 and E3 and then create a new relation S

R {R}


Case 8-b:All one cardinalitiesAll total participationR has attributes Foreign

key

Attribute Types: Required Vs Optional


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yp q p

Required Attribute - its value mustbe supplied

by the user. It cannotbe left blank (not null). Example: IDNo

Position

Optional Attribute - a field that may be leftblankbecause:

the information may exist but is not currentlyknown, or

because the field doesn't apply to the record at

all.

Example: Phone No

skills

professional exams

Convert the ERD into Relational Schema


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A

a

1

a2

a3

B

b

1

b2

b3

R1

R3

1 1M

Nr1

E

e1

e2

R4

1

N

R

2r2

C

c1

C2

F

f1

f2

R5

r4

D

d1

d2

N

N

M

r

3R6

1N

r5

M

N

C3

C C Cf f

d3

d4

Documents

Lecture 03 ERD to Relational