Download Data Modeling [Comparison of data modeling techniques ]

Data Modeling
[Comparison of data modeling
techniques ]
By
Renjini
Sindhuri
Contents





Introduction
E-R modeling
 Peter Chen
 Information Engineering
 Barkers Notation
 IDEFIX
UML modeling
XML modeling
 X- Entity modeling
 XUML
Conclusion
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
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
Peter –Chen developed E-R model
Peter –Chen notation




Entities are represented in the squared cornered and
circles as attributes
Many –Many relationships can be represented without
associative entity
Relationship itself has attributes and are considered
as objects
It failed to represent unique identifier
Peter Chen’s Model
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
Information Engineering model diagram
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 interaction
or another kind of association
Relationship names are prepositions and not verbs
Unique identifiers can be represented by hash marks
next to the attribute
Barkers Notation diagram
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
IDEFIX diagram
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
UML diagram
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.
XML notation
An example of XML notation
http://www.essentialstrategies.com/publicat
ions/modeling/xml.htm

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)
X entity model diagram
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
XUML diagram
UML and XUML model of a book store
Comparison of data modeling techniques
S.No
Modeling
Technique
Peter Chen
Information
Engineering
IDEFIX
Richard
Barker’s
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 )
Comparison of Data modeling techniques
S.No
Modeling
Technique
Peter Chen
Information
Engineering
IDEFIX
Richard
Barker’s
notation
UML
4.
Cardinality
Many to Many
relationships
can be
represented
between the
entities
without the
associative
entity
Can represent
Can represent
in different
ways
Can represent
zero or more
,atleast
at least one
express more
complex
upper limits,
zero, 3, 6-7,
or 9
Cannot
represent the
sub types and
sub-types can
be
represented
inside their
super-type
5.
Sub types/
Super Types
super type
6.
Unique
Identifier
Cannot
represent
,
up to many
up to one
relationships
sub-types can
be
represented
inside their
super-type
box
box
Sub types can
be
represented
as separate
entity boxes
separate from
its super type.
Cannot
represent
Represented
in the form of
Represented
in the form of
hash next to
Can represent
Can represent
Comparison of Data Modeling techniques
S.No
Modeling
Technique
Peter Chen
Information
Engineering
IDEFIX
Richard
Barker’s
notation
UML
7.
Aggregation
Cannot
represent
Cannot
represent
Cannot
represent
Cannot
represent
Can
represent
only binary
aggregations
8.
Business
Rules /
Cannot
Represent
Cannot
Represent
Cannot
Represent
Cannot
Represent
Can
Represent
Components
Comparison of Data Modeling techniques
S.No
Modeling
Technique
9.
Peter Chen
Information
Engineering
IDEFIX
Richard
Barker’s
notation
UML
High
Medium
Low
High
High
Aesthetic
Simplicity
Score
10.
Completenes
s Score
Low
medium
medium
medium
medium
11.
Language
Notation
Score
medium
medium
low
medium
High
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.
Contd..

XUML is more expressive, precise and
understandable.
 More rigorous and accurate.
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 XML
schemas
The distinctive features of XUML made this technique
of data modeling the latest trend for conceptual
modeling of data.
References

1. Conceptual Modeling of XML schemas, Bernadette Farias
Losio,Ana Carolina Salgado , Year: 2003,Publisher: ACM

2. XML conceptual modeling with XUML, HongXing Liu
HuaZhong 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 of
Publication: 2006, Publisher: ACM Press

3. PETER PIN-SHAN CHEN, “The Entity Relationship ModelToward a Unified View of Data” , Massachusetts Institute of
Technology, ACM Transactions on Data base System Volume1,
Issue 1,Publisher-ACM

4. Data modeling in the understanding database course: adding
UML and XML modeling to the traditional content. Journal of
Computing Sciences in Colleges, Volume 17, Issue 5 (April 2002)
References

5. Data Modeling101.
http://www.agiledata.org/essays/dataModeling101.html
6.A comparison of Data Modeling ,David C Hay,Essential Strategies
Inc,October 1999.