System Development

System Development

• The need for information system development
• System Development
• Different approaches to system development
• Factors influencing each approach and CASE.

The need for information

STEMS DEVELOPMENT

Many business organizations require systems to perform their operations in other ensure tangible
and intangible benefits such as increased operational efficiency and improved customer service.

These systems do not exclude MIS and some of is subsets like Payroll , inventory systems and
others. The need for information system development is itemized below under objectives of systems.

SYSTEMS DEVELOPMENT

Systems Development is a process that explores both the modification of old systems and the
creation of new ones from the discoveries of a problems or opportunities to the implementation of
a suitable information products that is maintainable over the period of time as a result of change in
information needs, business conditions and technologies.

Approaches to System Development

There are a number of approaches to Systems Development process depending on the type of
problem at hand , either one of these approaches or combination of the approaches may be
used,

namely:

i.) Traditional Systems Development Life Cycle,
ii.) Prototyping approaches, and
iii.) End-User Development approaches.

Factor influencing application of SDLC

- There is significant experiment with the type of systems to be designed.

- Many important systems features can be readily identified before development begins.

- Data requirement can be identified in advance.

- Management requires a comprehensive picture of the system before
Management requires a comprehensive picture of the system before giving approval.

- The development staff is not experienced with prototyping tools .

i.) Prototyping approach of system development

is sometimes called Rapid Application
Design (RAD) is building a working model of a new system in order to evaluate it ,
test it or have it approved before building the final product.

It can be used by both

analyst and end users where the end user requirements are hard to formulate or define.
Some development tools used in prototyping include :

o Integrated data dictionaries
o Very high-level languages
o End-user query languages
o Report writer.

Factor influencing application of prototyping

i.) users do not have a feel for the information or system capabilities they require.

ii.) User needs are changing rapidly

iii.) There is little experience with the type of system under development

iv.) The risk associated with delivering the wrong system is high.

v.) Many alternative design strategies must be tested.

vi.) The system must be developed quickly and at the lowest possible cost.

iii.) End-User Development approach of systems development is where end users can
develop new or improved ways to perform their jobs without the direct involvement of IT
professionals.

It involves use of modeling packages to achieve result.

It carries out its
activities either seeing the development from traditional SDLS or prototyping approaches. The
application development capabilities built into a variety of end user software packages have
made it easier for many users to develop their own computer-bases solutions.

For example;
you can use an electronic spreadsheet package as a tool to develop a way to easily analyze
weekly sales results for sales manager in a company or database management package to
design data-entry displays to help sales clerks enter sale
clerks enter sales data and others.

COMPUTER – AIDED SOFTWARE ENGINEERING

This is a software that provides tools to help with every phase in systems development and
enables developers to create data flow diagrams , data dictionary entries, and structure charts ; also
methodology that uses microcomputers and software, as well as procedures to aid the system
developer.

Special CASE software ‘toolkits’ can be purchased and would normally contain the following:

A graphics tool specifically designed to aid the drawing of data flow diagrams, system flowcharts
and entity-relationship models.

An interface generator to allow the speedy prototyping on screen dialogues, menus and reports.

A source code generator which will generate the source code from a system specification into
the source code of the chosen computer language.

A data dictionary development tool; this is particularly important in the development of database
system.

A Project Management tool to allow the scheduling of all activities such as
analysis design ,
programming and testing,
and the allocation of resources such as people and equipment to
the project.