Modeling 478 Final Ppt (1)

7/29/2019 Modeling 478 Final Ppt (1)

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Data Modeling[Comparison of data modeling

techniques ]

By

Renjini

Sindhuri


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Contents

Introduction

E-R modeling

Peter Chen

Information Engineering

Barkers Notation IDEFIX

UML modeling

XML modeling

X- Entity modeling XUML

Conclusion


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Introduction

Data modeling is the act of exploring data oriented

structures.

Examines and compares different data modeling

techniques

In the data modeling techniques we have traditional

modeling and object oriented modeling of data


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E-R modeling

It is a conceptual data model that views the real world

as consisting of entities and relationships

It is used to transform relational tables that are easy to

understand that enables easy communication with the

end user

PeterChen developed E-R model


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PeterChen notation

Entities are represented in the squared cornered and

circles as attributes

ManyMany relationships can be represented without

associative entity

Relationship itself has attributes and are considered

as objects

It failed to represent unique identifier


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Peter Chens Model


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Information Engineering model

Developed by Clive Finkelstein

Entities are represented in the squared cornered and

attributes are not shown at all they are shown in a

separate list called entity list

Relationships like mandatory 1 and many can be

represented

Unique identifiers are not represented


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Information Engineering modeldiagram


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Barkers Notation

Adopted by Oracle corporation for its CASE method

Entities can be represented by round cornered

rectangle

Same entity can be represented for role an interactionor another kind of association

Relationship names are prepositions and not verbs

Unique identifiers can be represented by hash marks

next to the attribute


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Barkers Notation diagram


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IDEFIX Notation

It is a modeling technique that is used by many

branches of the United States Federal government

A relationship name is a verb

IDEFIX shows subtypes as separate entity boxes IDEFIX permits multiple inheritance and multiple type

hierarchies


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IDEFIX diagram


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UML

UML is an object modeling technique

It models object classes instead of entities

In the object oriented world the relationships are called

as associations Cardinality and optionality in UML is conveyed by

characters or numbers

Express in the form of more complex upper and

lower limits UML introduces a small flag that includes text

describing any business rules


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UML diagram


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XML Notation

Describing data and interchanging structured and

unstructured data on the Internet

It is a universal language of data on web XML tags are used to create data structures

XML documents have been widely used for

interchanging data between heterogeneous systems.


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XML notation

An example of XML notation

http://www.essentialstrategies.com/publica

tions/modeling/xml.htm
http://www.essentialstrategies.com/publications/modeling/xml.htmhttp://www.essentialstrategies.com/publications/modeling/xml.htmhttp://www.essentialstrategies.com/publications/modeling/xml.htmhttp://www.essentialstrategies.com/publications/modeling/xml.htm


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X-Entity model

Conceptual model of XML uses X entity model in order

to represent additional features

The entity can be denoted by E

({A1,.An},{R1,Rm},{D1,.Dk}) Each attribute A is associated with a domain Dom(Ai)

Which specifies its value set

Cardinality is denoted by Card(Ai)=(min,max)


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X entity model diagram


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XUML

XUML comprises the characteristics of XML and

UML2.

It is used to express the containment semantics more

explicitly

Supporting the concept of Business Components

Specifying the data dependencies in multiple context


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XUML diagram

UML and XUML model of a book store


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Comparison of data modeling techniques

S.No Modeling

Technique

Peter Chen Information

Engineering

IDEFIX Richard

Barkers

notation

UML

1. Entities squared

cornered

and circles

as attributes

Squared

cornered,

attributes are

not shown at

all.

Round or

square

cornered

rectangle

Round

cornered

rectangle

Models object

classes

2. Relationship Nouns. So

the

relationships

can be

represent as

objects and

has

attributes

Verbs Verb or verb

phrase

Preposition

not verb

Associations

3. Constraints

between

relationships

Failed to

represent

the

constraints

directly

exclusive

or)

Can

represent

Constraints

exclusive or

,inclusive

Cannot

represent

Can

represent

Constraints

exclusive or)

Can

represent

Constraints

exclusive or )


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Comparison of Data modeling techniques

S.No ModelingTechnique Peter Chen InformationEngineering IDEFIX RichardBarkers

notation

UML

4. Cardinality Many to Many

relationships

can be

representedbetween the

entities

without the

associative

entity

Can represent Can represent

in different

ways

Can represent

zero or more

,atleast

at least one

up to many,up to one

relationships

express more

complex

upper limits,

zero, 3, 6-7,or 9

5. Sub types/

Super TypesCannot

represent the

sub types and

super type

sub-types can

be

represented

inside their

super-type

box

Sub types can

be

represented

as separate

entity boxes

separate from

its super type.

sub-types can

be

represented

inside their

super-type

box

Can represent

6. Unique

Identifier

Cannot

represent

Cannot

represent

Represented

in the form of

Represented

in the form of

hash next toCan represent


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Comparison of Data Modeling techniques

S.No Modeling

Technique


Engineering

IDEFIX Richard

Barkers

notation

UML

7. Aggregation Cannot

represent

Cannot

represent

Cannot

represent

Cannot

represent

Can

representonly binary

aggregations

8. Business

Rules /

Components

Cannot

Represent

Cannot

Represent

Cannot

Represent

Cannot

Represent

Can

Represent


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Comparison of Data Modeling techniques

S.No Modeling

Technique


Engineering

IDEFIX Richard

Barkers

notation

UML

9.

Aesthetic

SimplicityScore

High Medium Low High High

10. Completenes

s Score

Low medium medium medium medium

11. Language

Notation

Score

medium medium low medium High


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Advantages of XUML

XUML can express the containment semantics more

accurately.

Support the concept of Business Component.

Can specify the data dependencies in

multiple context.


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Contd..

XUML is more expressive, precise and

understandable.

More rigorous and accurate.


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Conclusion

By comparing the aesthetic simplicity, completeness,

language notation (relationship) Mr. Barker's notation

is favorable for requirement analysis model

XML is used in recent trends it follows a standard

format for representing structured and semi structured

data on web

X-Entity model has the advantages of both XML

schemas and extends the ER model so that it can

explicitly represent important features of XMLschemas

The distinctive features of XUML made this technique

of data modeling the latest trend for conceptual

modeling of data.


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References

1. Conceptual Modeling of XML schemas, Bernadette FariasLosio,Ana Carolina Salgado , Year: 2003,Publisher: ACM

2. XML conceptual modeling with XUML, HongXing LiuHuaZhong University of Science and Technology, P. R. China,YanSheng Lu HuaZhong University of Science and Technology,P. R. China,Qing Yang Wuhan Uni Pages: 973 976, Year ofPublication: 2006, Publisher: ACM Press

3. PETER PIN-SHAN CHEN, The Entity Relationship Model-Toward a Unified View of Data , Massachusetts Institute ofTechnology, ACM Transactions on Data base System Volume1,Issue 1,Publisher-ACM

4. Data modeling in the understanding database course: addingUML and XML modeling to the traditional content. Journal ofComputing Sciences in Colleges, Volume 17, Issue 5 (April 2002)


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References

5.Data Modeling101.http://www.agiledata.org/essays/dataModeling101.html

6.A comparison of Data Modeling ,David C Hay,Essential StrategiesInc,October 1999.

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Modeling 478 Final Ppt (1)