Over view of system analysis and design

System Analysis and Design

Saroj Dhakal

LecturerTrinity International College,

Kathmandu, Nepal

Objectives Define the terms system, system analysis, and system design.

Types of systems.

Describe the principal functions of the systems analyst.

List and describe the phases of the systems development life cycle.

Describe the various data gathering and analysis tools.

Describe a selection of systems design tools.

Alternative approaches to Structured analysis & Design to the SLDC

Explain the role of the maintenance task in the systems development life cycle.

Chapter 1

Overview of Systems Analysis and Design

System Analysis and Design: what is it?

Firstly we will define the system, than system analysis and system design as well.System:o Term system is derived from the Greek word

‘Systema’ which means an organized relationship among functioning units or components.

o A system is an orderly grouping of interdependent components linked together according to a plan to achieve a specific objective.

Systems Analysis and Design

Characteristics of a System

•Organization •Interaction •Interdependence •Integration •Central Objective

Elements of a System

•Outputs and Inputs •Processor •Control •Feedback •Environment •Boundaries and Interface

System Analysis

The dissection of a system into its component pieces to study how those component pieces interact and work.

(1) The survey and planning (2) The study and analysis (3) The definition

System Design

The process of defining the architecture, components, modules, interfaces and data for a system to satisfy specified requirements.


Need for System Analysis and Design

Installing a system without proper planning leads to great user dissatisfaction and frequently causes the system to fall into disuse

Lends structure to the analysis and design of information systems

A series of processes systematically undertaken to improve a business through the use of computerized information systems


Roles of the System Analyst

The analyst plays a key role in information systems development projects.

Must understand how to apply technology to solve business problems.

Analyst may serve as change agents who identify the organizational improvement.


Qualities of the System Analyst

Working knowledge of information technology Computer programming experience and expertise General problem solving skill General knowledge of business process and terminology Good interpersonal communication skills Good interpersonal relations skills Strong personal and professional ethics Self-disciplined and self-motivated Flexibility and adaptability


System Analyst Recommend, Design, and Maintain Many Types of Systems for Users


Strategic Level

Operational Level

Knowledge Level

Higher Level

A system analyst may be involved with any or all of these systems at each organization level

OPERATIONAL LEVEL

o It is a process of large amounts of data for routine business transactions.

o Automate handling of data about business activities (transactions)

o Process orientationo Support the day-to-day operations of the company

Example: Payroll Processing, Inventory Management Cash deposit and withdrawal system at bank used by the teller Computerized attendance system at school and college.


Transaction Processing System (TPS)

KNOWLEDGE LEVEL

Office Automation System (OAS) Supports data workers who share information, but do not usually

create new knowledge Examples: Word processing, Spreadsheets etc.

Knowledge Work System (KWS) Supports professional workers such as scientists, engineers, and

doctors Examples: computer-aided design systems, virtual reality systems.


Higher Levelo Management Information System (MIS)• To supports data worker who share information but do not usually create new

knowledge.• Converts raw data from transaction processing system into

meaningful form• Data orientation• Example: Word processing, Spreadsheets, Desktop publishing, Email

Electronic scheduling, Communication through voice mail, Email, Video

o Expert System (ES)

• Captures and uses the knowledge of an expert for solving a particular problem which leads to a conclusion or recommendation.

• Examples: MYCIN ( is an early expert system, or artificial intelligence (AI) program, for treating blood infections. In 1972 work began on MYCIN at Stanford University in California.


Decision Support Systems (DSS)

◦Designed to help decision makers◦Provides interactive environment for decision

making◦ Involves data warehouses, executive

information systems (EIS)◦Database, model base, user dialogue◦ Examples: financial planning with what-if analysis,

budgeting with modeling

Note:A data warehouse is a subject-oriented, integrated, time-variant and non-volatile collection of data in support of management's decision making process. For example, "sales" can be a particular subject.

Executive Support System (ESS) Helps executives to make unstructured strategic decisions in an informed

way Examples: drill-down analysis, status access

Group Decision Support System (GDSS) Permit group members to interact with electronic support Examples: email

Computer-Supported Collaborative Work System (CSCWS) CSCWS is a more general term of GDSS. It may include software support called

“groupware” for team collaboration via network computers. Example: video conferencing, Web survey system

Strategic Level


Information System (IS)

An arrangement of people, data, processes, and information technology that interact to collect, process, store and provide as output the information needed to support an organization.

Integrating New Technologies into Traditional Systems

Ecommerce and Web Systems.

Enterprise Resource Planning Systems.

Wireless Systems.

Open Source Software.


Systems analysts need to be aware that integrating technologies affects all types of system


Ecommerce and Web Systems

Benefits Increasing user awareness of the availability of a service,

product, industry, person, or group.

The possibility of 24-hour access for users.

Improving the usefulness and usability of interface design.

Creating a system that can extend globally rather than remain local, thus reaching people in remote locations without worry of the time zone in which they are located.


Enterprise Resource Planning Systems (ERPS)

Performs integration of many information systems existing on different management levels and within different functions

Example: Oracle


Oracle Database (commonly referred to as Oracle RDBMS or simply as Oracle) is an object-relational database management system produced and marketed by Oracle Corporation

Wireless Systems System analyst may be asked to design standard or wireless

communication networks that integrate voice, video and email into organizational intranets or industry extranets

System analyst may also be asked to develop intelligent agents

Example: Telecommunication services

Wireless communication is referred as m-commerce (mobile commerce)


An extranet is a private network that uses Internet technology and the public telecommunication system to securely share part of a business's information or operations with suppliers, vendors, partners, customers, or other businesses

An intranet is a private network, accessible only to an organization's staff. Generally a wide range of information and services from the organization's internal IT systems are available that would not be available to the public from the Internet

Open Source Software (OSS) An alternative of traditional software development where

proprietary code is hidden from the users

Open source software is free to distribute, share and modify

Characterized as a philosophy rather than simply the process of creating new software

Example: Linux Operating System, Apache Web Server, Mozilla Firefox Web browser,, and Joomla.


Systems Development Life Cycle (SDLC)Traditional methodology used to

develop, maintain, and replace information systems.

Phases in SDLC:◦ Planning◦ Analysis◦ Design◦ Implementation◦ Maintenance

Standard and Evolutionary Views of SDLC

Systems Development Life Cycle (SDLC) (Cont.)

Planning o An organization’s total information system needs

are identified, analyzed, prioritized, and arranged.o Project management begins Project management is the application of knowledge, skills, tools and techniques to project activities to meet project requiremento Inputo Initiation/ Investigation – highest levelo System concepts developmento Tools used: Gantt chart (for project scheduling)


Analysiso System requirements are studied

and structured.o Gathering system requirements.o Documentationo Know scope, constraints, risk and

costs Tool usedo DFD diagramo WBS (work breakdown structure)


Design – a description of the recommended solution is converted into logical and then physical system specifications.

Logical design – all functional features of the system chosen for development in analysis are described independently of any computer platform.

Process viewTools : UML diagramActivities diagrams

Systems Development Life Cycle (SDLC) (Cont.)Physical design – the logical

specifications of the system from logical design are transformed into the technology-specific details from which all programming and system construction can be accomplished.

Data viewTools : ERD diagramCommunication sequenceDimensional model

ToolsLogical UML diagrams (unified modeling

language) standardized general purpose modeling language in the field of object oriented software engineering.

Activity diagram – graphical representation of workflow.

Physical ERD (Entity relationship diagram) is

notational way to describe relationships in a diagram.

Systems Development Life Cycle (SDLC) (Cont.)Implementation – the

information system is coded, tested, installed and supported in the organization.

ExecuteCoding/ Construct systemTestingInstalling

Systems Development Life Cycle (SDLC) (Cont.)Maintenance – an information system is systematically repaired and improvedMaintaining the systemSupportingTraining Updating/ ImprovingRepairing

FEASIBILITY ANALYSES

Technical Feasibility: can we build it?

Economic Feasibility: should we build it?


TECHNICAL FEASIBILITY: CAN WE BUILD IT?

Familiarity with application: less familiarity more risk.

Familiarity with technology: less familiarity generates more risk.

Project size: large projects have more risk.

Compatibility: the hard it is so integrate the systems with the company’s existing technology, the higher the risk will be.


ECONOMIC FEASIBILITY: SHOULD WE BUILD IT?

Development Costs.

Annual operating costs.

Annual benefits (cost saving and revenues).

Intangible costs and benefits.


Methodologies:-is used to execute a process

Examples(System analysis and design tools)oWaterfall approachoPrototypingoComputer-Aided Software

Engineering (CASE) Toolso Joint Application Design (JAD)oRapid Application Development

(RAD)oAgile Methodologies

oeXtreme Programming

Waterfall approacho Is one phase begins when

another competes with back tack or looping

Proso High control for the developerCons:o Increased time for developmento System requirement are locked

in and cannot be changed

Prototypingo Iterative development

process: oRequirements quickly

converted to a working system.

oSystem is continually revised.oClose collaboration between

users and analysts.

Prototyping (Cont.)

Computer-Aided Software Engineering (CASE) Tools

oDiagramming tools enable graphical representation.

oComputer displays and report generators help prototype how systems “look and feel”.

oAnalysis tools automatically check for consistency in diagrams, forms, and reports.

oCentral repository for integrated storage of diagrams, reports, and project management specifications

Computer-Aided Software Engineering (CASE) Tools (Cont.)

o Documentation generators standardize technical and user documentation.

o Code generators enable automatic generation of programs and database code directly from design documents, diagrams, forms, and reports

Computer-Aided Software Engineering (CASE) Tools (Cont.)

Proso Display a good look and feelo Creates graphical representation o Keep it in a central repository

Cons:oDifficult to use with existing system

Joint Application Design (JAD)oStructured process involving

users, analysts, and managers.oSeveral-day intensive

workgroup sessions.oPurpose: to specify or review

system requirements.

Rapid Application Development (RAD)

o Methodology to radically decrease design and implementation time.

o Involves: extensive user involvement, prototyping, JAD sessions, integrated CASE tools, and code generators.

Rapid Application Development (RAD) (Cont.)

Rapid Application Development (RAD) (Cont.)

Pros:o Decrease design and

implementation time

Cons:o High costo Meant for large project

Agile MethodologiesoMotivated by recognition of

software development as fluid, unpredictable, and dynamic.

oThree key principlesAdaptive rather than predictive.Emphasize people rather than roles.Self-adaptive process.Pros: Flexible, AdaptiveCons: Heavy customer interaction

eXtreme Programmingo Short, incremental

development cycles.o Automated tests.o Two-person programming

teams.

eXtreme Programming (Cont.)

Pros: o Communication between

developerso High level of productivity.o High-quality code.Cons: o Requires lots of communication

with developer who are not necessarily good at communicating with individual who

are not technical

Education

Over view of system analysis and design