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Conceptual System Design
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In the conceptual design stage that the alternative overall
MIS designs are conceived and the best one is selected by
the system analyst in consultation with the
top management. The feasibility of meetingthe management objectives for the MIS is assessed
showing how the system will work at the high level is
drawn. Therefore, conceptual design is also known as
gross design; high level becomes the basis for
the detailed MIS design.
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Conceptual Design Steps
1. Defining problems in more details.
2. Refining the management objectives to set system
objectives.
3. Establishing system constraints.4. Determining information needs and their sources.
5. Developing alternative designs and selection one from
these various designs.
6. Document the conceptual design and preparing thereport.
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1. Define the problem-
The most important is that what are usually lacking
are clear definitions of the problems and the priority
system on the basis of problem is the main solution.Therefore, management must take the first step in
MIS design by formulating problems to be solved.
The problem can be solved by the iterative process.
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3. Establish System ConstraintsSystems constraints are also known as problem
boundaries or restrictions, constraints enable the designer
to stipulate the conditions under which objectives may be
attained and to consider the limitations that restricts the
design.Constraints may be viewed as a negative limitation on
systems design, there is a positive benefit also.
Establishing constraints will help to ensure that the design
is realistic.
Constraints may be classified as
External Constraints
Internal Constraints
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4. Determining Information needs
and sources
Information Needs :-For a good system design, a clear
statement of information needs is very important and
necessary.
Information Needs:- The information that can increase the
ability of managers in critical areas such as problems,
alternatives, opportunities and plans.
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The development of a concept of a system is a creative process
that involves synthesizing knowledge into some particular
pattern. The concept of an MIS would consist of the major
decision points, patterns of information flow, channels of
information and roles of managers and competitors.
It is obvious that each alternative concept of a system has
advantages and disadvantages. Sometimes one concept willdominate all others by major criteria.
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6. Document the best design
Sufficient information has been accumulated to begin a more
detailed description of the system concept. The manager should be involved to the extent that the system
provides the information required, the designer is concerned
with the nature of the materials and equipment as well as with
technical processing considerations.
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Design Methods
There are a no. of methods for designing information systems.
Following is a brief description of some of the popular
methods.
Problem Partitioning
Structured Design
Top-Down Design
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Problem Partitioning
The method is based on the principle of divide and
conquer. In this method, instead of solving the entireproblem at once, the problem is divided into small
manageable parts that can be solved separately.
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Structured Design
In this method, a structured chats is created , which
can be used to implement the system. The chart
depicts modules defining each module by the specific
function. Various tools like flow-charting , data flow
diagrams, structure charts, structured English, etc. are
used in a structured design.
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Top-Down DesignThe top-down design is based on the concept of a
system which suggests that a system consists of sub-
system, which have sub-system of their own. In otherwords, a system may be termed as a hierarchy of sub-
systems, the highest level sub-system corresponding
to the total system.
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Detailed System Design
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detailed system design is to prepare a
blue print of a system that meets the
goals of the conceptual system design
requirements.
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Detailed system design involves the following phases.
Project Planning and control
Involves the User
Define the Detailed Sub-SystemsInput/output Design
Feedback from the User
Database Design
Procedure DesignDesign Documentation
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Project PlanningIn order to ensure an effective and efficient design of
the MIS, it is very important that a detailed design
process should in itself be considered a complete
project. Some of the main points which are importantin planning and control of a detailed design are given
below.
Project Planning
Project Control
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Formulate the project Objectives.
Define the project task.
Prepare a network diagram of all events andactivities so as to specify sequential and parallel
events.
Schedule the work as per the requirements of the
user.
Prepare a budget for the project.
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Get a feedback of the actual performance of the
project with respect to time, cost and work of the
project and compare it with schedules, budgets andtechnical plans.
Take corrective action where required so as to
maintain control.
Project Control
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Involve the User
System designer must inform the users regarding the
new information system being developed and gain
their support and acceptance. It is also important to
take users in confidence so as to obtain information forthe design of the system. This will also help managing
resistance to change and would ensure successful
implementation of the system.
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Detailed Sub-System DefinitionIn detailed system design, every system needs to be broken down to
ascertain all activities required and their respective inputs and
outputs. In some of the cases, sub-systems are broadly defined in
the conceptual design phase, but at this stage they are specifically
defined to work out every detail concerning the sub-system,
Decomposition of the system to operational activities in general iscarried out as follows.
System
Sub-system
Functional ComponentTask
Sub-task
Operation element
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Wherever needed, integration of activities into a
sub-system may be done on the basis of any one or
more of the following common features.
Common functionsCommon techniques or procedures
Logical flow relationships
Common outputs or inputs
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Output/Input Design
As the main purpose of MIS is to provide information to aid
decision-making, to the user, output/input is one of the most
important characteristics of the information system. As
decisions are based on the output from the system and inputto the system, system designers must give this phase the
attention it deserves. The following paragraph will highlight
the key point to be considered while preparing output and
input design.
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Output design
The term output implies any information printed or
displayed, produced by an MIS. At this stage, the following
activities take place.
Specific outputs which are required to meet the informationneeds are identified.
Methods for presenting information are selected, and
Reports, formats or other documents that act as carrier of
information, produced by an MIS, are designed.
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Objectives of Output Design
It should provide information about the past, present or future events.
Outputs at the operational control level provide information of the past and
present events, whereas outputs which are required at the strategic planning
level include information on the future projections.
It should signal important events, opportunities and problems. For example,exceptional reports indicate such happenings.
It should trigger an action in response to some event. A set of rules is pre-
defined for such a trigger. For example, an order is prepared when inventory
reaches a certain level.
It should confirm an action as a result of some transaction. For example,
printing a receipt upon receiving the telephone bill.
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Presentation of Output
Details dominate the contents
Contents are classified in groupsTotal are to be drawn and comparisons are to be
made.
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Output Design SpecificationsPaper size: The designer must specify the size of the paper to be
used for the output, e.g. A4 size, A3 size, etc., or 9.5x11 inches,
11x14.7/8 inches or 8x14.7/8 inches etc.
Special Forms: Output can be designed on the pre0printed form
where standard print headings/titles, etc., are required.
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Sl. No. Item code Qty Ordered
Sigma Industries Ltd.
Purchase order
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Multiple Copies of Output: When more than one copy is required from thesystem, multiple copies are to be produced. This can be achieved by using
multipart forms. Multiple papers are available in carbon and carbonless forms.
Turnaround Documents: The output may be designed as a turnaround document,
if the organization uses optical scanners for reading data from the forms. Thus, ina turnaround document, the output later comes back as an input document.
Output layout: the arrangement of items on the medium is known as an output
layout. The layout design acts as a blueprint that guides the programmer in the
development of codes.
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The output layout should have the following.
Headings and date
Data and detailsSummaries and totals
Page title, number and date
Notes and comments
Column heading and data type. Designers usually use N (n) for numeric data
type and X (n) for alpha data type,-specifies the width of the column.
Total Pages N(2)
Emp. Code Name Amount Account No. Remark
X(4) X(20) N(8) X(4) X(25)
ABC Pvt. Ltd.
Salary Statement for the month N (2)
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Generally, output from a system is regarded as the
main determinant of the systems performance, yet
as already mentioned; outputs from the system are
affected by the inputs to the system. Therefore,
input design is equally important for the system
designer.
Input Design
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Control the volume of input data: try to reduce data
requirements and avoid capturing unnecessary data.
Constant and system- computable data should not be
captured.
Avoid processing delays during data entry: Automatingdata capturing may reduce this delay.
Avoid data entry errors: Checks in the data entry programs,
which are called input validation techniques may help.
Keep the process simple: the system should be kept assimple and easy to use as possible.
Objectives of Input Design
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Customer order Code: X(4) Date:
Sr. No. Item Code Qty. Ordered
1 X(4) N(4)
2
The input layout should contain the following.Heading and date of data entry.
Data heading and value.
Data type and width of the column.
Initials of data entry operator.
Fig. 3 illustrates an input layout design.
ABC Pvt. Ltd.
Customer Order Form
Input Layout
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Feedback from the User
Having specifically defined sub-systems, output and
inputs, the designers once again involves the users to get
feedback. This step will increase the acceptance of theMIS being designed. The system analyst should
demonstrate the proposed MIS to the users of the
system sub-system. This step will also reassure the top
management of the user organization that the detailed
design project is progressing as per plans.
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Database Design
A database is an orderly arrangement of all
the records related to each other. It serves
as a data resource for the MIS of anorganization. To have optimum
performance, storage and fast retrieval of
data, database design is an important phase
in the detailed design of a system.
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For designing a database the designer should keepthe following points in mind.
Identify all data tables and record types
Identify fields for each table, the key fields for
each table and relations between various tables.
Determine the data type and width for each field of
the tables.
Normalise the data tables.
Properly document data dictionary.
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Procedure Design
Procedures are the rules, standards or methods
designed to increase the effectiveness of the
information system. The procedures detail about
the tasks to be performed in using the system.
They serve as ready reckoners for the designers
as well as for the users.
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There is a wide variety of procedures, which include:
Data Entry Procedures: These are the methods designed for
data entry, e.g. data entry sequence.
Run-time Procedures: The actions to be taken by the users to
achieve the intended results, e.g. a procedure may instruct theuser to load printer with a specific size of paper.
Error-handling Procedures: these procedures help the user in
detecting and correcting errors.
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Security and backup Procedures: Through theseprocedures information is provided regarding actions
required to be taken to protect the system against damage.
Software Documenting Producers: The programmers get
instructions on how to document the programs.
In designing procedures, designers should:Understand the purpose and quality standard of each
procedure
Develop a step-by-step direction for each procedures,
andDocument all the procedures.
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Design Documentation
Detailed design starts with the
performance specifications given by the
conceptual design and ends with a set ofdesign specifications for the
constructions of MISD. The outputs from
the detailed design.
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Design documentation of detailed design report, generally, consists
of-
System objectives
Design constraints
Inputs/outputs
Data filesProcedures (manuals)
Proposed system (a summary and detailed flow charts)
Input/output specifications
Program specificationsDatabase specifications
Cost of installation and implementation and
System test conditions.
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Conclusion
System analysis is carried out with the help of certain tools, usually
known as structured analysis tools. The main tool, which are used for
analyzing and documenting the system specifications are data flow diagram,
data dictionary, structured English, decision trees and decision tables.
The main objective of the system design is to produce system
specifications, which can then be converted into an information system for
use in the organization. However the system design is a creative activity and
is considered to evolve through two different levels of design, i.e. conceptual
design and detailed design. The system specifications, called the detailed
system design or logical system design provide all detail of inputs, outputs,
files, database, controls and procedures. For ensuring an effective, efficientand successful MIS, the system analyst must not rush through this phase,
rather each and every step must be undertaken very carefully to prepare a
meticulous system design.
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