Object orianted Analysis and Design has emerged as the most practiced method for analysis and design of information system. An object is any thing of interest in the real world that is being modeled.  For more such innovative content on management studies, join WeSchool PGDM-DLP Program: http://bit.ly/welingkarshybridDlp Join us on Facebook: http://www.facebook.com/welearnindia Follow us on Twitter: https://twitter.com/WeLearnIndia Read our latest blog at: http://welearnindia.wordpress.com Subscribe to our Slideshare Channel: http://www.slideshare.net/welingkarDLP

1. Welingkar’s Distance Learning Division
I.T. for Management
CHAPTER-10
Determining Information Need
Object analysis
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2. Welingkar’s Distance Learning Division
Determining Information Need
Object analysis
Object Analysis & Design
OOAD has emerged as one of the most practiced
method for analysis & design of information system
The OOAD helps to conceptualize a system in a very
Generic fashion and yet relate very closely to the real
world system
The OOAD offers the benefit of process, structure and
data all in one Seamless technology
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3. Welingkar’s Distance Learning Division
Determining Information Need
Object analysis
What is an Object ?
An object is any thing of interest in the real world that is
being modeled
• Properties of objects:
• Unique Identifier
• Plays role in the system
• Described by attributes
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4. Welingkar’s Distance Learning Division
Determining Information Need
Object analysis
Typical Objects
• External entities
• Things
• Occurrences or events
• Roles
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5. Welingkar’s Distance Learning Division
Determining Information Need
Object analysis
Typical Objects
• Organizational units
• Places
• Structures
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6. Welingkar’s Distance Learning Division
Determining Information Need
Object analysis
Typical Objects (Examples)
Physical objects :
Desks ,computers, Text books etc.
Human Object
Faculty, Student etc.
Conceptual objects:
Course, Batch, Subject
Documentation related:
Invoice, ledger, Delivery invoice
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Objects View of the world
Vs Dataflow view
Data flow analysis believes that an information system is
a combination of flow, store and Transformation of
data, which the system must be able to demonstrate
Object view of the information system suggests
that the system is composed of several objects
The study of information system is really the
understanding of the desired behavior of a system to
various external and internal
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8. Welingkar’s Distance Learning Division
Objects Oriented approach (OOA):
The approach to conducting an OOA is as follows
• Study the system
• Identify as many objects as possible
• Understand the object relationship
object: automobile
attributes:
Make
Model
body type
Price
options code
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9. Welingkar’s Distance Learning Division
Objects Oriented approach (OOA):
The approach to conducting an OOA is as follows
• Study the system
• Identify as many objects as possible
• Understand the object relationship
object: automobile
attributes:
Make
Model
body type
Price
options code
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10. Welingkar’s Distance Learning Division
Objects Oriented approach (OOA)
What is a Relationship
• Relationship : indicates “connectedness”
• Properties:
• Several instances can exist
• Objects can be related
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11. Welingkar’s Distance Learning Division
Determining Information Need
Object analysis
Objects Oriented approach (OOA)
Cardinality and Modality
• Cardinality: Number of occurrence
• (1:1) one to one
• (1:m) one to many
• (m:n) many to many
• Modality: Relationship is optional / mandatory
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12. Welingkar’s Distance Learning Division
Objects Oriented approach (OOA)
Thus for instance in one school teachers teaches 60
students, guides upto 10 students & mentor for 3
student.
Each of these indicates the Cardinality of relation.
Cardinality also termed as business rules, for instance
other school numbers could be different
As a analyst it is important to identify these rules
The cardinality rules have a profound impact on the
Design of the business system
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13. Welingkar’s Distance Learning Division
Objects Oriented approach (OOA)
Identify business events & object related events
The events related to the objects are something that
can or has happened
Events can be Singleton events where in the objects
generates its own events and then responds.
For example Events related to Student object:
Comes late, remains absent, Attends lecture appears
exam
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14. Welingkar’s Distance Learning Division
How to use Event Analysis
• System is sum of object behavior
A thorough analysis of events at the system level as
well as object level leads to a comprehensive list of
behaviors which the system must be able to
demonstrate.
• The list of events acts as a Check list for conducting the
system analysis
The checklist helps in improving the quality of the
analysis
• Thus the list of behaviors also helps in working out the
scope and size of the programs to be developed
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15. Welingkar’s Distance Learning Division
How to use Event Analysis
• Associated programs with objects
Usually the object which seems to have a Control over
the behavior is the place where the method needs to be
assigned to.
• Data base design
OOA naturally leads to database design
Each object becomes table in a database for ex
student, faculty
Each relationship becomes table in a database for ex.
Teacher mentor examiner
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16. Welingkar’s Distance Learning Division
How to use Event Analysis
Keys & Attribute
What are keys:
Keys are essentially identifiers used to identify an object in a
table
• Primary keys
Apart from storage the ids make it easy to uniquely identify an
object in a table. Such ids/keys are known as primary key
• Combined key
In a table such as mentor Mr. Mehta is mentor for several
students hence his id will appear several times in a table.
Thus it is not a unique key. Thus every row in the mentor table is
unique but it requires a combined
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17. Welingkar’s Distance Learning Division
How to use Event Analysis
Keys & Attribute
• Secondary keys
Non unique keys are also known as secondary keys
Secondary keys are quite often used for answering certain
queries
• Foreign Keys
Keys in a database, which help to identify objects stored in
another table, are known as Foreign Keys .For example student id
key used in any other table like attendance table helps us to trace
name stored in the student master table. Foreign Keys are useful
to connect data across different tables in a database
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18. Welingkar’s Distance Learning Division
Determining Information Need
Object analysis
End of Chapter 10
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