Design of a Video Rental System - Essay Example

AL AFFILIATION: DESIGN OF A VIDEO RENTAL SYSTEM DETAILS: Introduction The aim of documenting a video rental system is to specify to the programmer what to code without having to write the program. The design needs to specify the working of the program. The design documentation should serve as its maintenance manual to the common users. The design is easier to understand than the code. The design matches the requirements of the program to the computer language. The technique used to deliver the design is modeling. A model can be defined as a simplified version of the expected system. This design consists of sets of models which capture the important features of the system. Inputs to System Design The following details are included in the inputs of a design system 1) Statement of Work 2) RD Plan 3) Current Situation Analysis 4) Proposed System requirements 5) A Recommendation explores an alternative or build Outputs for System Design The outputs may include: 1) Organizational and Infrastructure and changes for the proposed system 2) A data schema, often a relational schema 3) Metadata that defines the tables and data-items 4) A function hierarchy diagram describing the structure of the program 5) A pseudo code for each module in the program 6) A prototype for the proposed system The main content areas of an information system are data, process, infrastructure and organization. System design involves reviewing each of the content areas in order to solve the client’s problems when it becomes operational. Infrastructure defines the hardware and software components as essential to facilitate performing the activities of the system i.e. data storage and servers. System design involves modification of an organization in order to match the functioning of the system. It includes identifying persons who update, create or delete data. The data in the CDM are converted to data design. The process of system designing involves specifying the detailed system logic. Infrastructure This consists of elements such as the computers for database management systems, servers, telecommunications, and programming languages. Customer’s procedure, standards and policy manuals may bring constraints to the system design.11 The infrastructure design should specify the development environment. Critical issues under infrastructure include the following. •Language(s) of the system. This concern specifying what language and design approach will be is used to develop the system. Include versions, i.e. The system is a Client/Server system. The client wants Visual Basic language. The system will be installed in the computer using a run-time version • Host environment. Specify what machines will be used. Include how the machines will fit into the infrastructure, i.e. the system will be installed in the MIS Division, which that are attached to the College of Computer LAN. These machines have a processor, 64MB of RAM and 500MB of disk storage. • Network. For systems operating over a network it is always vital to specify network requirements. The issue is not in changing the network, but the impact of the new system. Large systems require new links and components. The design specifies the client, server, LAN and network requirements for the system. • Access. Specify the actions needed when accessing it for use or maintenance. • Security. The infrastructure finally identifies the access limitations and backup requirements. Organization During design, identification and description of any desired organizational changes are made. For example, the system may reassign and reschedule some of the roles performed by different people in the organization. In particular the design is expected to specify the following. • Who is the intended user of the information being generated and what for? • The actual users of the system. • Who will ensure the system runs and is well maintained. • The users responsible for running programs in the system. • The person responsible in making changes to the system. Data The design now has the specific data schema for the system. Conceptual data model (CDM) is converted into a data schema. The data schema is composed of relational tables, objects, other kinds of tables and flat files. A relational schema is prepared from a relational database management system (RDMS). Oracle designer helps in converting the CDM into the relational table schema Process Design documentation requires physical models. A physical model maps itself directly onto the system the way it is to be built. Module and flow names should always be the same both in the model and in the code. Attributes are to have the same names in the database as in the model. The call and triggering sequences are specified and match that in the code. The specifications in logic vary from project to project. The main requirements for logic specification are: 1. Representing the structure of the logic in an appropriate graphical form 2. Specifying the detailed logic within each module shown on the graphical representation in the program code. All data transfers to and from the tables or externals is captured on a Physical Data Flow Diagram. A Data Flow Diagram is a tool for showing data access in a system. A Modified Data Flow Diagram keeps track of triggers. Data flow diagrams track data usage throughout the system. The flow of data drives the appropriate execution of a system. Data flow diagrams are developed to capture the fundamentals of systems. Implementation Once design through all its activities, implementation activities begin. During implementation, software is constructed or bought, tested, and then implemented. After implementation the information system can be delivered to the stake holder for use. Various technologies can be adopted to implement the design system12. Service architecture This is the physical design of a service that includes all the resources used by a service. It includes databases, backing stores and software components. The service contract is documented to formalize what the individual service capabilities require. The service architecture is a reference point for evolving the service and measuring the impacts of changes in the service. Service composition architecture Services which are composition centric potentially address vital requirements by recomposing same services in different styles. It is a composition of all individual architectures of the participating services. It documents service level agreements and service contracts23. Service inventory architecture It is composed of services that are used automate business processes. The service inventory architecture is documents from the service inventory blueprint in order for all service candidates to be redesigned before they are implemented. Works Cited Coronel, Carlos, Steven Morris, and Peter Rob. Database principles: fundamentals of design, implementation, and management. 9th ed. Australia: Course Technology Cengage Learning, 2011. Stojanoric, Dahanayake Ajantha Service-oriented Software System Engineering: Challenges and Practices. Hoboken: Wiley, 2005. Wasson, Charles S.. System analysis, design, and development concepts, principles, and practices. Hoboken, N.J.: Wiley-Interscience, 2006. Read More