Introduction. There are two main approaches to systems

Added on - 22 Sep 2019

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IntroductionThere are two main approaches to systems development. These are; the structuredapproach and the object-oriented approach. The structured approach follows the structuredanalysis, design and programming techniques. The programming language employed herefollows a sequence of statements where each statement executes at every decision point. Ittypically consists of a set of repeated statements. More sophisticated programs are divided into ahierarchy of programs in a top-down approach. Programs at the top module calls the lower oneduring execution(Valacich, 2015). These modules should be highly cohesive and looselycoupled. The structured analysis part of the approach makes it easier for the system developer toidentify the system process requirements and the data requirements, and the interrelates of theprocesses in the system towards the realization of a common goal.On the other hand, the object-oriented approach models the information system as a collection of interrelated objects workingtogether to achieve a common goal. An object is an entity that is able to respond to the messages.The object-oriented analysis identifies the objects that carry out certain tasks coupled with theuser events that are necessary for their accomplishment (Kendall & Kendall, 2014). The objectoriented design shows graphically how these objects interact to achieve their functions. Theobject-oriented programming finally writes down the actual code that is necessary to accomplishthese functions in an information system. This project utilizes object-orienteddesign, whereby alist of functional and non-functional requirements are produced alongside ause case model of thesystem with separate descriptions of the use cases, a list of candidateclasses and an initial classdiagram.
Functional RequirementsFunctional requirements defines a set of inputs and outputs that specifies the overallbehaviour of the system. These may include; business rules, legal requirements, externalinterfaces, certification and reporting requirements, authorization and authentication levels andthe business administrative rules(Valacich, 2015). From theDerby Auctioneers', theserequirements include; customer log in process, online item bidding, bid withdrawal, determiningwinning bid, payment for item, uploading item photos, updating items and shipping the items tothe customerNon-FunctionalRequirementsThe non-functional requirements define the criterion employed in specifying the systembehaviour as opposed to the specification of the these behaviours. These requirements include;system performance, reliability, interoperability, scalability, availability, capacity, recoverability,usability, maintainability, serviceability and manageability. These requirements also focus onthe environmental aspects of the system, regulatory, security and data integrity.From theDerbyAuctioneers' case study, these requirements include;'the system should optimally utilize itscomputing resources', 'the reliability, interoperability, scalability, availability, capacity,recoverability, usability, maintainability, serviceability and manageability of the system must bemet and maintained' and 'the data the integrity of the data contained within the system must besecured from unauthorized access and modification.
Use case modelSystemSystem UserAdmin (Ken)(John)Derby AuctioneersInformation SystemLog into the systemLog into the systemBrowse through Item photosBid on ItemsPay for won itemsPost item photosDetermine winning bidShip item to the customer
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