Typical SDLC

1
Typical SDLC

• Feasibility study
• Plan
• Analysis
• Design
• Development)
• Testing
• Validation
• Implementation
• Get ready to start again

2
System analysis II User Involvement

• To overcome reluctance to change, involve the
  people in the client organization in the
  development process.

3
An analyst must be good at

• coordinating schedules and system-related tasks
  with a number of people.
• communicating -The analyst may need to make oral
  presentations and write reports for clients,
  users, and others involved with the system.
• Other desirable qualities of a systems analyst
  are
• an analytical mind
• self-discipline
• self-direction
• The ability to work without tangible results

4
Systems Analysis III

• During this phase the systems analyst must
• Gather data
• Analyze data
• Determine system requirements
• Report to management

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Gathering Data

• The systems analyst relies on the following
  sources when gathering data
• Written documents
• Interviews
• Questionnaires
• Observations
• Sampling

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• Written Documents
• Gathering documents includes procedures manuals,
  forms, and any kind of material that might have
  bearing on the problems in the organization.
• Interviews
• There are two types of interviews,
• Structured interviews include only preplanned
  questions.
• Unstructured interviews allow the systems analyst
  to digress from the formal line of questioning.

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Questionnaires

• Questionnaires are ideal for gathering
  information from a group too large to interview.

8
Observation

• Systems analysts must observe the flow of
  information in and out of an organization.
• Sometimes this requires them to be a temporary
  participant in the organization.

Sampling

• Sampling is the collection of data about
  quantities, costs, time periods, and other
  factors relevant to the system.

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Analysing the data

• Analysts use a number of tools to help them
  understand the IS
• Scope diagrams where does the IS start and
  finish
• Hierarchy charts what modules does the IS need
• Input Processing Output (IPO) charts
• Often, analysts start looking at the whole
  system, then progressively break it down into
  smaller and smaller parts - this is called
  decomposition

10
Prototyping

• Prototyping is the development of a working
  model of part or all of an IS. Prototyping is
  used
• to get a better idea of the functional
  requirements (what the IS does)
• or to refine some detail of the user interface
• For smaller applications or applications where it
  is VERY hard to define a comprehensive set of
  requirements, prototyping may be the predominant
  method. In evolutionary prototyping, the
  prototype eventually becomes the application,

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System Requirements

• The final segment of the systems analysis phase
  leads to a list of the things the system must be
  able to do.
• This list of system requirements will determine
  the design of the new system.

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Step 3. Systems Design

• This is the phase in which the systems analyst
  actually plans the new system.
• There are a number of tools used to help design
• The way data will be organised,
• The functions that will be provided
• The type of user interface

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Data Flow Diagrams (DFDs)

• DFDs serve as a map of how data flows in and out
  of an organization and reveal procedures used.
• DFDs use standard symbols to represent data
  movement

An entity that is the source or destination of
data
Data storage
A process that changes data
Direction of flow of data
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Customer file
12.1
Generate report
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Decision Tables/Trees

• Unlike a data flow diagram, a decision table
  represents the logical decisions that must be
  made regarding potential conditions in a given
  system.

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Entity Relationship Models

• Show how different entities are related. This is
  useful for determining database structures

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Data dictionary
Name Description Format Coded
TITLE Complete title of book X(150) N
ISBN Intnl Std Book No 9(13) N
AUTHOR Name of Author X(25) N
CARDNO Patron card number 9(4) Y
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Detail Design

• The systems analyst must now develop detailed
  design specifications, such as
• Output requirements
• Input requirements
• Files and databases
• Systems processing
• Systems controls and backups

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Output Requirements

• The systems analyst must determine
• what the client wants the system to produce.
• the medium of the output.
• the type of reports needed.
• the contents of the output.

Input Requirements

• The systems analyst must determine what input is
  required to give the desired output.
• what forms will be used.
• what sources will provide input

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Files and Databases

• The systems analyst will determine whether the
  files should be stored sequentially, directly, or
  by some other method.
• File storage must also be coordinated with the
  databases used by the client.

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Systems Controls and Backup

• Systems controls are designed to prevent fraud
  and tampering.
• In addition, system files should be backed up
  (copied) and the copies stored in a safe manner
  and location.

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Interface design

• Specialist interface designers and graphic
  artists often work out how the IS will look and
  behave from a users point of view.
• They design the flow from one function to
  another and how individual functions may be
  carried out. They are concerned with the location
  of edit fields, icons etc on the screen
• They plan the colours and sizes of items on the
  screen to make it easier and more pleasant to use