Typical SDLC

Feasibility study Feasibility study Plan Plan AnalysisAnalysis DesignDesign Development)Development) TestingTesting ValidationValidation ImplementationImplementation

Get ready to start againGet ready to start again

System analysis II User Involvement

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

coordinating schedules and system-related tasks coordinating schedules and system-related tasks with a number of people.with a number of people.

communicating -The analyst may need to make communicating -The analyst may need to make oral presentations and write reports for clients, oral presentations and write reports for clients, users, and others involved with the system.users, and others involved with the system.

Other desirable qualities of a systems analyst are:Other desirable qualities of a systems analyst are: an analytical mindan analytical mind self-disciplineself-discipline self-directionself-direction The ability to work without tangible resultsThe ability to work without tangible results

An analyst must be good at:An analyst must be good at:

Systems Analysis III

During this phase the systems analyst must:During this phase the systems analyst must: Gather dataGather data Analyze dataAnalyze data Determine system requirementsDetermine system requirements Report to managementReport to management

Gathering Data

The systems analyst relies on the following The systems analyst relies on the following sources when gathering data:sources when gathering data: Written documentsWritten documents InterviewsInterviews QuestionnairesQuestionnaires ObservationsObservations SamplingSampling

Written DocumentsWritten Documents Gathering documents includes procedures Gathering documents includes procedures

manuals, forms, and any kind of material that manuals, forms, and any kind of material that might have bearing on the problems in the might have bearing on the problems in the organization.organization.

InterviewsInterviews There are two types of interviews, There are two types of interviews, Structured Structured interviews include only preplanned interviews include only preplanned

questions.questions. UnstructuredUnstructured interviews allow the systems interviews allow the systems

analyst to digress from the formal line of analyst to digress from the formal line of questioning.questioning.

Questionnaires Questionnaires are ideal for gathering information Questionnaires are ideal for gathering information

from a group too large to interview.from a group too large to interview.

Observation Systems analysts must observe the flow of Systems analysts must observe the flow of

information in and out of an organization.information in and out of an organization. Sometimes this requires them to be a temporary Sometimes this requires them to be a temporary

participant in the organization.participant in the organization.

Sampling Sampling is the collection of data about Sampling is the collection of data about

quantities, costs, time periods, and other factors quantities, costs, time periods, and other factors relevant to the system.relevant to the system.

Analysing the data

Analysts use a number of “tools” to help them Analysts use a number of “tools” to help them understand the ISunderstand the IS

Scope diagrams; where does the IS start and finishScope diagrams; where does the IS start and finish Hierarchy charts; what modules does the IS needHierarchy charts; what modules does the IS need Input Processing Output (IPO) charts; Input Processing Output (IPO) charts;

Often, analysts start looking at the whole system, Often, analysts start looking at the whole system, then progressively break it down into smaller and then progressively break it down into smaller and smaller parts - this is called decompositionsmaller parts - this is called decomposition

Prototyping

Prototyping is the development of a “working Prototyping is the development of a “working model” of part or all of an IS. Prototyping is usedmodel” of part or all of an IS. Prototyping is used to get a better idea of the functional to get a better idea of the functional

requirements (what the IS does)requirements (what the IS does) or to refine some detail of the user interfaceor to refine some detail of the user interface

For smaller applications or applications where it is For smaller applications or applications where it is VERY hard to define a comprehensive set of VERY hard to define a comprehensive set of requirements, prototyping may be the predominant requirements, prototyping may be the predominant method. In “evolutionary prototyping”, the method. In “evolutionary prototyping”, the prototype eventually becomes the application,prototype eventually becomes the application,

System Requirements The final segment of the systems analysis phase The final segment of the systems analysis phase

leads to a list of the things the system must be able leads to a list of the things the system must be able to do.to do.

This list of system requirements will determine the This list of system requirements will determine the design of the new system.design of the new system.

Step 3. Systems Design

This is the phase in which the systems analyst This is the phase in which the systems analyst actually plans the new system.actually plans the new system.

There are a number of tools used to help design There are a number of tools used to help design The way data will be organised,The way data will be organised, The functions that will be providedThe functions that will be provided The type of user interface The type of user interface

Data Flow Diagrams (DFDs)

DFDs serve as a map of how data flows in and out of an DFDs serve as a map of how data flows in and out of an organization and reveal procedures used.organization and reveal procedures used.

DFD’s use standard symbols to represent data movementDFD’s 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

customer

report

Customer file

Generate report

12.1

Decision Tables/Trees

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

Select withdrawal

Pin OKY

N

Balance OK

Y

N

Entity Relationship Models Show how different entities are related. This is Show how different entities are related. This is

useful for determining database structuresuseful for determining database structures

copy

book author

Barcode

1

m

m n

11

Data dictionary

NameName DescriptionDescription FormatFormat CodedCoded

TITLETITLE Complete title of bookComplete title of book X(150)X(150) NN

ISBNISBN Intn’l Std Book NoIntn’l Std Book No 9(13)9(13) NN

AUTHORAUTHOR Name of AuthorName of Author X(25)X(25) NN

CARDNOCARDNO Patron card numberPatron card number 9(4)9(4) YY

Detail Design

The systems analyst must now develop detailed The systems analyst must now develop detailed design specifications, such as:design specifications, such as: Output requirementsOutput requirements Input requirementsInput requirements Files and databasesFiles and databases Systems processingSystems processing Systems controls and backupsSystems controls and backups

Output Requirements The systems analyst must determine:The systems analyst must determine:

what the client wants the system to produce.what the client wants the system to produce. the medium of the output.the medium of the output. the type of reports needed.the type of reports needed. the contents of the output.the contents of the output.

Input Requirements

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

Files and Databases The systems analyst will determine whether the The systems analyst will determine whether the

files should be stored sequentially, directly, or by files should be stored sequentially, directly, or by some other method.some other method.

File storage must also be coordinated with the File storage must also be coordinated with the databases used by the client.databases used by the client.

Systems Controls and Backup

Systems controls are Systems controls are designed to prevent fraud and designed to prevent fraud and tampering.tampering.

In addition, system files In addition, system files should be backed up (copied) should be backed up (copied) and the copies stored in a safe and the copies stored in a safe manner and location.manner and location.

Interface design

Specialist interface designers and graphic artists Specialist interface designers and graphic artists often work out how the IS will look and behave often work out how the IS will look and behave from a users point of view. from a users point of view.

They design the “flow” from one function to They design the “flow” from one function to another and how individual functions may be another and how individual functions may be carried out. They are concerned with the location carried out. They are concerned with the location of edit fields, icons etc on the screenof edit fields, icons etc on the screen

They plan the colours and sizes of items on the They plan the colours and sizes of items on the screen to make it easier and more pleasant to usescreen to make it easier and more pleasant to use