Systems analysis and design methods 7th whitten and benley chapter 17

Systems ImplementationThe Construction Phase of Systems Implementation  Introduction  The purpose of the construction phase is twofold:  To build and test a functional system that f

Systems Implementation

Introduction

 The chapter will address the following questions:

 What is the systems implementation process in terms of the

construction and delivery phases of the life cycle?

 Can you describe the systems implementation phases in terms of your information building blocks?

 Can you describe the systems implementation phases in terms of purpose, activities, roles, inputs and outputs, techniques, and steps?

Systems Implementation

What is Systems Implementation?

 What is Systems Implementation?

 Systems implementation is the construction of the new system

and the delivery of that system into production (meaning day operation)

day-to-Systems Implementation

Delivery Phase

Production Information System Approval to Continue Project

Systems Implementation

The Construction Phase of Systems

Implementation

 Introduction

 The purpose of the construction phase is twofold:

 To build and test a functional system that fulfills business and design requirements, and

 To implement the interfaces between the new system and existing production systems.

 The project team must construct the database, application

programs, user and system interfaces, and networks

 Some of these elements may already exist (subject to enhancement)

Database Structures

Database Scehma

FOCUS ON SYSTEM DATA

Application Programs

Application Schema

FOCUS ON SYSTEM PROCESSES

Component Programs

Interface Schema

FOCUS ON SYSTEM INTERFACES

Software (and Hardware) Technology (and standards)

Interface

Technology (and standards)

Networking Telchnology (and standards)

Network Programs Network Schema

FOCUS ON SYSTEM GEOGRAPHY

Construction Phase

FAST Methodology

CREATE TABLE CUSTOMER

(customer_no CHAR(10) NOT NULL

customer_name CHAR(32) NOT NULL

customer _rating CHAR(1) NOT NULL

balance_due DECIMAL(5,2)

CREATE INDEX cust_no_idx on CUSTOMER

CREATE INDEX cust_rt_idx on CUSTOMER

O rder Fo rm Help +

Cust omer

Fo rm

Pro duct Lookup

Logon New Customer New Order Ord er Accepted Change

of Address First Order Request Order Help Order Help Complete Request Product Lookup Request Product Lookup Help Product Lookup Help C omplet e

On Event Help.ButtonClick Do Change Focus HelpDialog

On Event OKButton Do Begin {proecdure}

End

On Event CancelButton Do

Create AccountType = SalesClerk Set OrderDir.Rights=full Set CustomerDir.Rights=full Set ProductDir.Rights=read Set OrderAppDir.Rights=copy

O rder Processing

Pr ogram

Pr oces s Initiat ion Routine Shutdown Rout ine

G et an Order Validate File an

O rder Check

Cus tome r Credit Che ck Product Data Check Data Release

an

O rder Cust ome rs Product s Or de rs

St Louis Mainframe

Indy AIX Server

NT Server LA

NT Server NY Communications Controller

PBX

Enternet LAN AIX/Lan Manager Ethernet LAN/NT

PERFORM CREDIT_CHECK

IF CREDIT_CHECK 'BAD' THEN

Systems Implementation

Build and Test Networks

Build and Test Databases

Network Design Requirements

Network Details

DatabaseDesign Requirements

Revised Database Schema and Test Data Details

Databases

New Databases

Database Structure

Quality Assurance

Install and Test New Software Package

System Vendors

Software Packages and Documentation

Modified S/W Specs and New Integration Requirements

Integration Requirements

& Program Documentation

Software Package New Programs & Reusable S/W Components

Program Documentation

Technical Design Statement, Plan For Programming, and Test Data

• System Owners and system users - not involved in this activity.

• System analyst - The systems analyst’s role is more in terms of a

facilitator and ensures that business requirements are not compromised by the network solution

• Network designer - The network designer is a specialist in the

– Network administrator - This person has the expertise for

building and testing network technology for the new system He/she will also be familiar with network architecture

standards that must be adhered to for any possible new networking technology

 Prerequisites (Inputs):

 This activity is triggered by the approval from the system owners to continue the project into systems design

 The key input is the network design requirements defined

during systems design.

 The principle deliverable of this activity is an installed

network that is placed into operation.

 Network details will be recorded in the project repository for

future reference.

 Applicable Techniques:

 Skills for developing networks are becoming an increasingly important skill for systems analyst especially given the industry trend toward downsizing existing applications

 The following steps are suggested to complete this activity.

• Step 1 - Review the network design requirements outlined in the

technical design statement developed during systems design

• Step 2 - Make any appropriate modifications to existing networks

and/or develop new networks

• Step 3 - Revise network specifications for future reference

Systems Implementation

The Construction Phase of Systems

Implementation

 This task must immediately precede other programming activities

because databases are the resources shared by the computer programs to

 This activity will typically be completed by the same system

specialist that designed the databases

• System owner and system users - are not involved in this activity.

• Systems analyst - (optional) When the database to be build is a

non-corporate, applications-oriented database the systems analyst often

• System builder - is primarily responsible for this activity.

• Database administer - When the database to be build is a corporate database, the database administrator will be play a large role in completing this activity.

 Prerequisites (Inputs):

 The primary input to this activity is the database design

requirements specified in the technical design statement during

systems design

 The end-product of this activity is an unpopulated database

structure for new database

• The term unpopulated means that the database structure is implemented but that data has not been loaded into the database structure

 Revised database schema and test data details are also

produced during this activity and placed in the project repository for future reference

 Sampling Sampling methods are used to obtain representative

data for testing database tables

 Data Modeling This activity requires a good understanding of

data modeling

 Database Design Understanding database design requirements

is essential for completing this phase

 Steps:

 The following steps are suggested to complete this activity.

• Step 1 - Review the technical design statement for database design

requirements

• Step 2 - Locate production databases that may contain

representative data for testing database tables Otherwise, generate test data for database tables

• Step 3 - Build/modify databases per design specifications.

• Step 4 - Load tables with sample data.

• Step 5 - Test database tables and relationships to adding,

modifying, deleting, and retrieving records All possible relationships paths and data integrity checks should be tested

• Step 6 - Revise database schema and as necessary for future

reference

• System owner and system users - are not involved in this activity.

• Systems analyst - (optional) The systems analyst typically

participates in the testing of the software package by clarifying requirements

• System designers - The system designer may be involved in

clarification of integration requirements and program documentation that is used in testing the software

• System builder - is primarily responsible for this activity.

– Applications programmer - The applications programmer (or

programming team) is responsible for the installation and testing of new software packages

– Network Administrators - Network administrators may be

involved in actually installing the software package upon the network server

 The main input to this activity is the new software packages

and documentation that is received from the system vendors.

 The applications programmer will complete the installation and

testing of the package according to integration requirements

and program documentation that was developed during

system design

 The principle deliverable of this activity is the installed and

tested software package(s) that are made available in the

software library

 Any modified software specifications and new integration requirements that were necessary are documented and made available in the project repository to provide a history and serve as future reference.

 There are no specific techniques applicable to this activity

Successful completion of this activity is primarily dependent upon programming experience and knowledge of testing.

 Steps:

 The following steps are suggested to complete this activity.

• Step 1 - Obtain the software packages and review documentation.

• Step 2 - Install the software package.

• Step 3 - Conduct tests upon the software packages to ensure that it

works properly - making revisions as necessary

 This activity is specific to the applications programmer

• System owner and system users - are not involved in this activity.

• Systems analyst - (optional) The systems analyst typically serves merely in clarifying business requirements to be implemented by the programs.

• System designers - The system designer may be involved in clarification of the programming plan, integration requirements, and program documentation (developed during systems design) that is used

• System builder - is primarily responsible for this activity.

– Applications programmer or programming team - The

applications programmer is responsible for writing and testing in-house software

– Application tester - an application or software tester specializes

in building and running test scripts that are consistently applied

to programs to test all possible events and responses

 The primary input to this activity is the technical design

statement, plan for programming, and test data that was

developed in during systems design

 Since any new programs or program components may have already been written and in use by other existing systems, the experienced applications programmer will know to first check

for possible reusable software components available in the

software library

Systems Implementation

The Construction Phase of Systems

Implementation

 Prerequisites (Inputs): (continued)

 Some information systems shops have a quality assurance group staffed by specialists who review the final program

documentation for conformity to standards

recommendations and requirements (OPT).

 Deliverables (Outputs):

 The principle deliverable of this activity is the new programs

and reusable software components that are placed in the

software library

 This activity also results in program documentation that may

 If modules are coded top-down, they should be tested and

debugged top-down and as they are written

 There are three levels of testing to be performed: stub testing, unit or program testing, and systems testing.

they be main program, subroutine, subprogram, block, or paragraph

been coded and stub tested are tested as an integrated unit

written in isolation work properly when they are integrated into the total system

 The following steps are suggested to complete this activity.

• Step 1 - Review the design specifications

• Step 2 - Develop a detailed programming plan

– (Optional) Formulate the project team and assign

responsibilities

– Write and document programs and perform unit testing.

– Review program documentation for quality standards Note

that this step may be required in some organizations

– Conduct system testing to ensure all programs work properly

together

 The following steps are suggested to complete this activity.

• Step 2 - Develop a detailed programming plan (continued)– (Optional) Update the project repository with revised program documentation for future referencing

– (Optional) Place new programs and reusable components in the software library

 Conduct a system test to ensure that the new system works properly.

 Prepare a conversion plan to provide a smooth transition to the new system

 Install databases to be used by the new system

 Provide training and documentation for individuals that will be using the new system

 Convert from the old system to the new system and evaluate the

project and final system

FOCUS ON SYSTEM DATA

Application Programs

FOCUS ON SYSTEM PROCESSES

Component Programs

FOCUS ON SYSTEM INTERFACES

Software (and Hardware) Technology (and standards)

Interface Technology (and standards)

Networking Telchnology (and standards) Network Programs

FOCUS ON SYSTEM GEOGRAPHY

FAST Methodology

CREATE TABLE CUSTOMER

(customer_no CHAR(10) NOT NULL

customer_name CHAR(32) NOT NULL

customer _rating CHAR(1) NOT NULL

balance_due DECIMAL(5,2)

CREATE INDEX cust_no_idx on CUSTOMER

CREATE INDEX cust_rt_idx on CUSTOMER

On Event Help.ButtonClick Do Change Focus HelpDialog

On Event OKButton Do Begin {proecdure}

End

On Event CancelButton Do

Create AccountType = SalesClerk Set OrderDir.Rights=full Set CustomerDir.Rights=full Set ProductDir.Rights=read Set OrderAppDir.Rights=copy

VALIDATE_AN_ORDER

REPEAT UNTIL NO_MORE_ORDERS PERFORM CUSTOMER_VALIDATIO REPEAT UNTIL NO_MORE_ORDER PERFORM PRODUCT_VALIDATI END REPEAT

PERFORM CREDIT_CHECK

IF CREDIT_CHECK 'BAD' THEN

Delivery Phase

Systems Implementation

Software Library Convert

to New System

System

Users

Conduct System Test

Prepare Conversion Plan

Train System

Successful System Test

Required Modifications

to Programs

Software Packages, Custom-Built Programs, & any Existing Programs

System Test Data

Design Specifications

Conversion Plan

User

Training &

Documentation

Appropriate Documentation

Restructured Existing Data

Database Schema

Existing Data

custom- Roles:

 The systems analyst facilitates this activity

• System owner and system users - are not involved in this activity.

• Systems analyst – The systems analyst typically facilitates this activity

by communicating testing problems and issues with the project team members.

• System designers - System designer specialists are typically responsible for testing integration requirements and resolving design

 Prerequisites (Inputs):

 The primary inputs to this activity include the software

packages, custom-built programs, and any existing programs comprising the new system.

 The system test is done using the system test data that was

developed earlier by the systems analyst

 As with previous tests that were performed, our system test may

result in required modifications to programs - thus, once again

prompting the return to a previous activity in the implementation phase

 This iteration would continue until a successful system test was

experienced

 Applicable Techniques:

 A good understanding of testing is essential

 Whereas this activity is concerned with systems testing, the

identification of program specific problems may necessitate a return

to previous activities and subsequent stub and unit level testing