Changing Data into Information Systems Systems Analysis Analysis Design Design Verification Verification Issues Issues Developing Developing and and Implementing Implementing Database Database Systems Systems Systems Analysis Design and Verification Issues of Developing and Implementing of Database Systems Systems Systems Analysis Analysis Design Design Verification Verification Issues Issues Developing Developing and and Implementing Implementing Database Database Systems Systems 4 Data are the raw facts that are stored in databases 4 Raw facts are seldom immediately useful to a decision maker 4 What the decision maker really needs is information which is defined as data processed and presented in a meaningful form Table 6 1 A Simple Tabulation Transforming Data into Information The Information System Systems Systems Analysis Analysis Design Design Verification Verification Issues Issues Developing Developing and and Implementing Implementing Database Database Systems Systems 4 A database is a carefully designed and constructed repository of facts and is part of larger whole known as an information system u u u An IS provides for data collection storage and retrieval IS also facilitates the transformation of data into information and the management of both data and information Components of an information system l l l l l l The Information System Systems Systems Analysis Analysis Design Design Verification Verification Issues Issues Developing Developing and and Implementing Implementing Database Database Systems Systems 4 The process of creating an IS is known as systems development 4 Applications transform data into the information 4 An application is composed of two parts the data and the code People Hardware Software Database s Application programs Procedures 4 The performance of an IS depends on three factors Generating Information for Decision Making Systems Systems Analysis Analysis Design Design Verification Verification Issues Issues Developing Developing and and Implementing Implementing Database Database Systems Systems 4 System analysis is the process that establishes the need for and the extent of an IS u Database design and implementation DB development u Applications design and implementation u Administrative procedures The Systems Development Life Cycle Systems Systems Analysis Analysis Design Design Verification Verification Issues Issues Developing Developing and and Implementing Implementing Database Database Systems Systems 4 The Systems Development Life Cycle SDLC traces the history life cycle of an IS 4 Database design takes place within the confines of an IS 4 Five phases of SDLC Figure 6 2 u Planning u Analysis u Detailed Systems Design u Implementation u Maintenance Figure 6 1 1 The Systems Development Life Cycle Systems Systems Analysis Analysis Design Design Verification Verification Issues Issues Developing Developing and and Implementing Implementing Database Database Systems Systems Systems Systems Analysis Analysis Design Design Verification Verification Issues Issues Developing Developing and and Implementing Implementing Database Database Systems Systems 4 Planning u The planning phase yields a general overview of the company and its objectives u An initial assessment of the information flow andextent requirements must be made l l l u A feasibility study must address the following issues if a new system is necessary l l The Systems Development Life Cycle Systems Systems Analysis Analysis Design Design Verification Verification Issues Issues Developing Developing and and Implementing Implementing Database Database Systems Systems 4 Analysis u u Problems defined during the planning phase are examined in greater detail l What are the precise requirements of the current system s end users l Do those requirements fit into the overall information requirements The existing hardware and software are studied l End users and system designer s work together to identify processes and potential problem areas 4 Detailed Systems Design u u u The Systems Development Life Cycle Systems Systems Analysis Analysis Design Design Verification Verification Issues Issues Developing Developing and and Implementing Implementing Database Database Systems Systems The designer completes the design of the system s processes including all technical specifications for l l l l Screen Menus Reports Other devices u Conversion steps are laid out u Training principles and methodologies are planned Technical aspects of hardware and software requirements The system cost The Systems Development Life Cycle Systems Systems Analysis Analysis Design Design Verification Verification Issues Issues Developing Developing and and Implementing Implementing Database Database Systems Systems The analysis phase is a thorough audit of user requirements l Should the existing system be continued Should the existing system be modified Should the existing system be replaced The analysis phase includes the creation of a logical system design l The logical design specifies conceptual data model inputs processes and expected output requirements l System design tools Data flow diagram DFD Hierarchical input process and output HIPO Entity Relationship E R diagrams Defining the logical system also yields functional descriptions FD of the system s components modules for each process within the database environment The Systems Development Life Cycle Systems Systems Analysis Analysis Design Design Verification Verification Issues Issues Developing Developing and and Implementing Implementing Database Database Systems Systems 4 Implementation u The hardware the DBMS software and application programs are installed and the database design is implemented u The system enters into a cycle of coding testing and debugging u The database is created and the system is customized u The database contents are loaded u The system is subjected to exhaustive testing u The final documentation is reviewed and printed u End users are trained 2 The Systems Development Life Cycle Systems Systems Analysis Analysis Design Design Verification Verification Issues Issues Developing Developing and and Implementing Implementing Database Database Systems Systems 4 Maintenance u End users requests for changes generate system maintenance activities u Three types of system maintenance l l l u Corrective maintenance in response to systems errors Adaptive maintenance due to changes in the business environment Perfective maintenance to enhance