Download Information System Analysis

Information System Analysis
Information System
Design
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Output Design Objective \ Introduction
Output:
 Information delivered to users through the
information system by way of intranets,
extranets, or the WWW
 Many forms: hard copy (printed reports), soft
copy (screens, microforms, audio)
 Analyst works closely with user to develop
output: after all, it’s FOR the user anyway
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Output Design Objective
Output should be designed to:
1.
Serve the intended purpose

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During
the
information
requirements
determination phase of analysis, the systems
analyst finds out what purposes must be
served and then output is designed based on
those purposes
Output Design Objective
2.
Design Output to Fit the User
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
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With many users, it’s hard to personalize
output
Try to design what many, if not all, users need
and prefer
Generally, it’s more practical to create userspecific or user customizable output when
designing it for a DSS or other highly
interactive applications such as those on the
Web
Output Design Objective
3.
Designing the Appropriate Quantity of Output
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More is not always better
Provide what each person needs to do his/her
work
Don’t overload just because the system can do it
Users usually want great amounts of output at
one time, especially when there’s an easy way to
access more information
Output Design Objective
4.
Making Sure the Output is Where It’s Needed

5.
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Make sure it gets presented to the right users
Providing the Output on Time
 Could be daily, monthly, quarterly, annually,
on exception, on demand
 Accurate
timing is critical in some
organizations
Output Design Objective
6.
Choosing the Right Output Method
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There are trade-offs for each method in terms
of cost, accessibility, flexibility, life spans,
distribution, storage and retrieval possibilities,
transportability, and overall impact of the data
Designing Screen Output
–
–
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Output is ephemeral (not permanent like printed
output)
Users must be instructed on which keys to press
to continue reading further screens and to interact
with the display
Access may be controlled via password; this is
not done with printed output
Designing Screen Output
Guidelines for Screen Design
–
–
–
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Keep the screen simple
Keep the screen presentation consistent
Facilitate user movement among screens
Create an attractive screen
Designing Screen Output
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Designing Screen Output
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Input Design Objectives
–
–
–
–
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Ease of Use
Effectiveness
Accuracy
Attractiveness
Simplicity
Consistency
Input Design Objectives
Guidelines for Input Screen Design:
– Making Forms Easy to Fill In
– Meeting the Intended Purpose
– Assuring Accurate Completion
– Keeping Forms Attractive
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Database Design

Designing data storage organization\
Objectives :
–
–
–
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Availability
Integrity (accurate & consistent)
Efficient storage of data as well as efficient
updating and retrieval.
The information retrieval be purposeful
Database Design

There are two approaches to the storage of
data in a computer system:
–
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Store the data in individual files each unique to a
particular application.
Store data in a computer-based system involves
building a database.
Database Design
Database: a database is a collection of non-redundant
data which can be shared by different
application systems
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Stresses the importance of multiple applications,
data sharing
Database becomes a common resource for an
agency
Database Design
Database: Changes can be made to data without
affecting other components of the system
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change format of data items (real to integer,
arithmetic operations)
change file structure (reorganize data internally or
change mode of access)
relocate from one device to another, e.g. from
optical to magnetic storage, from tape to disk
Database Design

Objectives of Effective Databases:–
–
–
–
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–
Ensuring that data can be shared among users for
a variety of applications.
Maintaining data \accurate & consistent.
Availability.
Evolving the needs of the users to grow.
Allowing users to construct their personal view of
the data.
Reduced cost of software development
security restrictions
Database Design \ Normalization

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A poor database design can cripple an
application,
producing
problems
with
redundancy, inaccuracy, consistency, and
concurrency of your data. Normalization is a
process that serves to reduce, if not
eliminate, these problems with data.
Normalization is the process of organizing
data in the database
Database Design \ Normalization
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Redundant data wastes disk space and creates
maintenance problems. If data that exists in more
than one place must be changed, the data must
be changed in exactly the same way in all
locations which is time consuming and prone to
errors.
Database Design \ Normalization

Inconsistent
dependency
is
a
database
design that makes certain assumptions about
the location of data.

Inconsistent dependencies can make data
difficult to access because the path to find the
data may not be logical, or may be missing or
broken.
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Database Design \ Normalization
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The three steps of data normalization are:
–
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Remove all repeating groups and identify the
primary key.
Ensure that all nonkey attributes are fully dependent
on the primary key.
Remove any transitive dependencies, attributes that
are dependent on other nonkey attributes.
Database Design \ Normalization

The process of normalization involves working through
well-defined steps, called normal forms.
1.
First Normal Form (1NF)
Second Normal Form (2NF)
Third Normal Form (3NF)
2.
3.
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Database Design \ Normalization
1.
First Normal Form (1NF):
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A database is said to be in First Normal Form
when all entities have a unique identifier or key,
and when every column in every table contains
only a single value and doesn't contain a
repeating group or composite field
Database Design \ Normalization
2.
Second Normal Form (2NF):
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A database is in Second Normal Form when it is
in First Normal Form plus every non-primary key
column in the table must depend on the entire
primary key, not just part of it, assuming that the
primary key is made up of composite columns.
Database Design \ Normalization
3.
Third Normal Form (3NF)
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A database is in Third Normal Form when it is in
Second Normal Form and each column that isn't
part of the primary key doesn't depend on
another column that isn't part of the primary key.
(Any Attribute depends on candidate key)
Database Design \ Normalization

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Additional normal forms have been defined, but
are less commonly utilized. These advanced
normal forms include Fourth Normal Form
(4NF), Fifth Normal Form (5NF), Boyce Codd
Normal Form (BCNF), and Domain-Key Normal
Form (DK/NF).
Designing User Interface

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The user interface is the system that helps
users communicate with the computer
system and/or the application system
Designing User Interface
User Interface Design Objectives:–
–
–
–
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Match the user interface to the task.
Make the user interface efficient.
Provide appropriate feedback to users.
Generate usable queries.
Improve productivity of knowledge workers.
Designing User Interface
Components of the User Interface:
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–
Presentation language, which is the computer-tohuman part of the transaction.
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Action language that characterizes the human-tocomputer portion.
Designing User Interface
Types of User Interfaces:
1.
Natural-language interfaces.
Natural-language interfaces permit users to
interact with the computer in their everyday or
"natural" language.
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Designing User Interface
Types of User Interfaces:
2. Question-and-answer interfaces.
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The computer displays a question for the user on
the screen.
The user enters an answer via the keyboard or a
mouse click.
The computer acts on that input information in a
preprogrammed manner.
New users may find the question-and-answer
interface most comfortable.
Designing User Interface
Types of User Interfaces:
3.
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A menu interface.
- A menu interface, that provides the user with
an screen list of available selections.
- A nested menu is a menu that can be reached
through another menu.
Designing User Interface
Types of User Interfaces:
4.
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Form – Fill Interface
- Form-fill
interfaces are onscreen forms
displaying fields containing data items or
parameters that need to be communicated to
the user.
- Form-fill interfaces may be implemented using
the Web.
Designing User Interface
Types of User Interfaces:
5.
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Command – Language Interfaces
- Allow the user to control the application with a
series of keystrokes, commands, phrases, or
some sequence of these.
- Require memorization of syntax rules.
- May be an obstacle for inexperienced users.