Systems analysis and design methods 7th whitten and benley chapter 02

Information System Building BlocksTransaction Processing System Executive Information System Management Information System Decision Support System Expert System Personal Information Syst

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Information System Building Blocks

Introduction

 The chapter will address the following questions:

they interoperate?

development?

development and the unique role of the systems analyst in relation

to the four groups?

managers who become stakeholders in systems development?

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Introduction

 The chapter will address the following questions:

relates to information systems architecture?

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A Review of Fundamentals of

Information Systems

 What is the difference between Data and Information?

transactions Most data items have little meaning and use by

themselves

processing and purposeful intelligence

 Information Systems transform data into useful

information.

processes, interfaces, and geography that are integrated for the purpose of supporting and improving the day-to-day operations in

a business, as well as fulfilling the problem-solving and making information needs of business managers

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decision-Information System Building Blocks

 Information technology has significantly expanded the power and potential of most information systems.

combination of computer technology (hardware and software) with telecommunications technology (data, image, and voice networks)

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 Transaction Processing Systems

of the business.

applications that capture and process data about (or for)

business transactions They are sometimes called data

processing systems.

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transaction processing systems with management

reports required to plan, monitor, and control business operations.

system application that provides for management-oriented reporting, usually in a predetermined, fixed format

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 Decision Support Systems

providing useful information to support the decision

process.

application that provides its users with decision-oriented information whenever a decision making situation arises When applied to executive managers, these systems are sometimes

called executive information systems.

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support to the decision maker:

(similar to exception reporting)

decision

a decision Sometimes this is called ‘what if’ analyses

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populated with detailed, summary, and exception information that can be accessed by end users and managers with DSS tools that generate a virtually limitless variety of information in

support of unstructured decisions

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captures the knowledge and expertise of a problem solver or decision maker, and then simulates the ‘thinking’ of that expert for those who have less expertise

technology, often called expert system shells.

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 Office Information Systems

all relevant information to all those who need it.

business office activities that provide for improved work flow and communications between workers, regardless of whether

or not those workers are physically located in an office

technologies:

• Electronic forms technology

• Work group technology

• Electronic messaging technology

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 Personal and Work Group Information Systems

typically are built using personal computer technology and software.

needs of a single user They are designed to boost an individual’s productivity

the needs of a work group They are designed to boost the group’s productivity

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Transaction Processing System

Executive Information System

Management Information System

Decision Support System

Expert System

Personal Information System

Office Information System

Business Database

Expertise Database

Business Data Warehouse

Data Data

Captured data

Data and messages

Read-only data

Data snapshots

Read-only data Data

Rules

Data

Problem

Decision support information Executive inquiry

Executive information

Any Manager

Any Decision Maker

or Executive

Information need

Management information

Any Relevant User Problem

Personal Files &

Databases

Personal data Personal

information

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A Framework For Information

Systems Architecture

 What is an Information Systems Architecture?

framework into which various people with different perspectives can organize and view the fundamental building blocks of

information systems

something “at stake” in determining the success of the system

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INFORMATION SYSTEMS FRAMEWORK

S Y S T E M A N A L Y S T S

SYSTEM BUILDERS

SYSTEM DESIGNERS

SYSTEM USERS

SYSTEM OWNERS

Data Technology

INFORMATION SYSTEM COMPONENTS (the actual, technical implementation of the system)

INFORMATION SYSTEM DESIGN (HOW the system will be implemented using technology)

INFORMATION SYSTEM REQUIREMENTS (WHAT the system "is" and "must do" independent of technology)

INFORMATION SYSTEM SCOPE (purpose and vision; goals and objectives; costs and benefits)

INFORMATION SYSTEM FOCUSES

Networking Technology

Interface Technology Software

Technology

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Perspectives - The People Side of

was coined to describe those people whose jobs involve the

creation, collection, processing, distribution, and use of

information

advocates They are usually responsible for budgeting the money and time to develop, operate, and maintain the information system They are also ultimately responsible for the system’s justification and acceptance

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the information system on a regular basis – capturing, validating, entering, responding to, storing, and exchanging data and

information

• Clerical and service workers

• Technical and professional staf

workers whose responsibilities are based on a specialized body of knowledge.

• Supervisors, middle managers, and executive managers

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 System Users

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 System Designers

constraints into technical solutions They design the computer files, databases, inputs, outputs, screens, networks, and programs that will meet the system users' requirements They also integrate the technical solution back into the day-to-day business

environment

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 System Designers

program) focus

have an INTERFACE focus

GEOGRAPHY focus

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 System Builders

based upon the design specifications from the system designers

In many cases, the system designer and builder for a component are one and the same

builder

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 The Role of the System Analyst

and validates their views

least) ensures that the technical views are consistent and

compatible with the business views

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Building Blocks - Expanding The Information System Framework

 There are at least four distinct focuses in a system.

out the mission of the business

systems

processes happen; where the interfaces happen

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S Y S T E M A N A L Y S T S

SYSTEM BUILDERS (components)

SYSTEM DESIGNERS (specification)

SYSTEM USERS (requirements)

SYSTEM OWNERS (scope)

System Builders' views of DATA

System Designers' views of DATA

System Users' views of DATA

System Owners' views of DATA

DATA FOCUS

Data Technology

System Builders' views of PROCESSES

System Designers' views of PROCESSES

System Users' views of PROCESSES

System Owners' views of PROCESSES

PROCESS FOCUS

System Builders' views of INTERFACES

System Designers' views of INTERFACES

System Users' views of INTERFACES

System Owners' views of INTERFACES

INTERFACE FOCUS

System Builders' views of GEOGRAPHY

System Designers' views of GEOGRAPHY

System Users' view of GEOGRAPHY

System Owners' views of GEOGRAPHY

GEOGRAPHY FOCUS

Networking Technology

Interface Technology Software

Technology

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S S T E M A A L Y T S (facilitation)

Database Technology

FOCUS ON SYSTEM DATA

COBOL Program Structure Chart Data Flow Diagram Decomposition Diagram

FOCUS ON SYSTEM PROCESSES

FOCUS ON SYSTEM INTERFACES

COBOL Compiler on IBM 3090 MVS

Interface

Telchnology

FOCUS ON SYSTEM GEOGRAPHY

Va lida te

c us tom e r produc tsVa lida te

Re le a se orde r

Cu stom e rs

Orde rs

Produc ts orde r cus tom e r num be r

re je cte d orde r

price s picking ticke t

R o utine

Get an

Or der Validate

an Or der File an

D ata

R elease

an

Or der

C usto mer s P r o ducts Or der s

VALIDAT E_AN _OR DER

R EPEAT UN T IL N O_M OR E_ORDER S PER FOR M CUSTOMER_VALIDATIO REPEAT U NTIL N O_M OR E_OR DER PER FOR M PRODUCT_VALIDAT I

EN D R EPEAT

PER FOR M CREDIT _CH ECK

IF CR EDIT _CHECK ' BAD' TH EN

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 Building Blocks of Data

technology

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Database Programs Database Schema Data Requirements

Business Subjects

Software Technology

Interface

Telchnology

Cust omers order zero, one, or more product s

CUS TOMER cus tome r-no cus tome r-na me cus tome r-ra ting

ba la nce -due

PRODUCT product-na me unit-of-me a s ure unit-price qua ntity-a va ila ble ORDER

orde r-no orde r-da te products -orde re d qua ntitie s -orde re d

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purpose or mission; or (2) things that must be managed or controlled in order to achieve business goals and objectives.

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system

should be implemented

entities, attributes, relationships, and rules Data requirements should be expressed in a format that is independent of the technology that can or will be used to implement the data.

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and databases

database schemas, file organizations, fields, indexes, and other technology-dependent components

the framework is a database schema.

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foundation

unforgiving languages

• The most commonly encountered database

construction language is SQL (Structured Query

Language)

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 Building Blocks of Processes

technology

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Database Structures Database Scehma Data Requirements

Business Subjects

Application Programs Application Schema

Business Process Reqts.

Business Functions

Software (and Hardware) Technology

Interface

Telchnology

R o utine Shutdo wn R o utine

Get an

Or der Validate an Or der File an Or der

Check Custo mer

Cr edit Check

P r o duct Data Check Data

EN D REPEAT

PERFORM CREDIT_CHECK

IF CREDIT_CHECK ' BAD' THEN

C he ck cre dit

Va lida te custom e r Va lida te pr oducts

Re le a se orde r

Cus tom e rs

Orde r s

Produc ts orde r custom e r num be r

va lid orde r

orde r w ithout

va lid custom e r

re je cte d orde r

pr ice s picking ticke t

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processes called business functions.

business Functions can be decomposed into other functions, and eventually, into discrete processes that do specific tasks.

function-centered That meant that the system supported one business

function or functional area

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redesigned as cross-functional systems.

• A cross functional information system supports relevant business

processes from several business functions without regard to traditional organizational boundaries such as divisions,

departments, centers, and offices.

business process redesign initiatives that are intended to

reinvent and streamline the way organizations do business

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outputs, as well as starting times and stopping times Some business processes happen repetitively, while others happen occasionally, or even rarely Business processes may be implemented by people, machines, computers, or a combination of all three.

• Specific policies and procedures underlie these business processes.

accomplishing a business process.

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architecture that specifies which software (and hardware)

technologies must be used

• An application schema is a model that communicates how

selected business processes are, or will be, implemented using the computer and programs

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computer programming languages that describe inputs, outputs, logic, and control

applications programs

representations of what a computer process is supposed to do, or how a computer process is supposed to accomplish its task.

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environment for prototyping computer processes

model of the information system using rapid application development tools (provided with most popular programming languages).

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