Incorporating object analysis and design into a structured information systems development life cycle

An object approach to information system development should be incorporated into the structured system design life cyde (SDLC) during the analysis and design phases. The tools of the structured approach (data flow diagrams, data structures, data stores, etc.) help to identify the relationships that exist between the data stores and the entities (objects) within an inprmation system. This is only a starting point at which the IS developer further evaluates me informational needs that are required within the information system. A listing of the data struc­ tures is generated to assodate the specific data elements that comprise each data structure. A series of logical steps (normalization) can be used to remove the redundancy and inflexibili­ ty within each data structure. The end result of the nonhalization process is the generation of an entity-relationship diagram (E-R diagram). The E-R diagram can be used as a reference point in which to apply a series of objed oriented analysis and design steps to insure that information coUeded on objeds throughout the organization is properly integrated into the SDLC. A revised diagram is subsequently used to modify the data flow diagrams which will be the basis for the design of the new system. Thus, the objed approach to information system development is an integral component of the structured system design life cyde. INTRODUCTION Information systems (IS) development has gone through several changes over the past twenty years. These changes were part of an evolutionary process involving the systematic approach to information systems development—traditionally referred to as the System Design Life Cycle (SDLC). Generally, these changes can be grouped into three stages: (1) structured methodology, (2) Computer-Aided Software Engineering (CASE), and (3) object orientation. Each stage helped to drfine an approach to information system/software development by placing more emphasis on analyzing and designing the solution to users' problems and less time on generating computer code and revising software that did not meet the needs of the users. The structured stage helped to identify a methodology thlat focused on the goals and objec­ tives of the organization and the underlying information system and subsystems that assimilate them into their related activities. With the introduction of Computer Aided Software Engineer­ ing (CASE)-tools, the IS developer was able to automate the SDLC and the structvued methodology. Currently, the object stage has emerged as an opposing methodology to the structured approach to information system development. Yet, \ry incorporating an object orien­ tation into the structmed approach to the SDLC, the IS developer can achieve the benefits of both structured methodology and object orientation. 49 1 Wallace: Incorporating object analysis and design into a structured inform Published by CSUSB ScholarWorks, 2014 Journal of International Information Management Volume 2, Number 2 STRUCTURED METHODOLOGY During the 1960s and early 1970s the development of information systems was an "undisciplined" approach resulting in poorly designed and implemented systems that did not meet the needs of the users who had to interact with them. These systems were often very difficult to control and to maintain. Information systems and software development was a costly effort in which supply fell short of the heavy demand for IS services. The IS developer (often the senior computer programmer) spent relatively little time on identifying users' needs and requirements, and more time on generating computer code (Souza, 1991). There was tremendous pressiure to reduce time and cost by rushing the development process in order to place a software product into the production cycle of the organization. This resulted in more time and money spent on testing and maintaining software that did not fully meet the needs of the user who requested it (Kendall, 1992). The structmed stage established a more disciplined approach to the IS development pro­ cess. This approach focused on the identification of the goals and objectives of the organiza­ tion and the underlying information system and subsystems that assimilate them into their rel&ted activities. IS developers incorporated the structure approach into a series of steps or phases that would become a blueprint for the development of future information systems. This blueprint is generally called the System Design Life Cycle (SDLC). The various phases of the SDLC are: (1) problem definition, (2) analysis, (3) design, (4) implementation, (5) in­ stallation, and (6) review (Powers, 1990). The structured approach uses a modeling tool called the data flow diagram to reveal the activities and data flows within an information system. This model becomes the basis for both understanding and recommending improvements to the existing system. System flowcharts and structme charts are generated from the data flow diagrams to provide more specific details needed to generate the computer code (if customiz­ ed coding is required) during the implementation phase of the SDLC. The initial three phases (problem definition, anal)^is, and design) are generally considered the front-end phases where the needs and requirements of the users are evaluated with respect to the goals and objectives of the organization and the information system tmder investiga­ tion. By focusing on the front-end phases of the SDLC, the IS developer is able to better meet the needs of the user and significantly reduce the costs associated with testing and maintain­ ing information systems (Kendall, 1992). The structured stage helped to change the SDLC so that more time was spent on the analysis and design phases and less on the coding activi­ ty. Figiue 1 demonstrates this change. With the introduction of Computer Aided Software Engineering (CASE) tools, the IS developer was able to automate the SDLC which allowed him/her to devote even more time to the analysis and design phases (see Figure 1). CASE technology has produced a wide range of automated tools which provided the IS developer many advantages: (1) emphasis on the analysis and design phases, (2) automated documentation, (3) automated auditing and design capabilities, (4) computer code generation, (5) reverse engineering, (6) design and code reusabflity, (7) prototyping, and (8) project administration. 50 2 Journal of International Information Management, Vol. 2 [2014], Iss. 2, Art. 4 http://scholarworks.lib.csusb.edu/jiim/vol2/iss2/4 Incorporating Object Anal^is Journal of International Information Management . Figiire 1. Comparison Software Development (Souza, 1991)