Chapter 9.1: The Systems Development Life Cycle (SDLC)
iterative development
consists of a series of tiny projects. It has become the foundation of multiple agile methodologies
bugs
(Part of testing) defects in the code of an information system
methodology
(maintenance) a set of policies, procedures, standards, processes, practices, tools, techniques, and tasks that people apply to technical and management challenges
business requirements
(part of the analysis phase) the specific business requests the system must meet to be successful, so the analysis phase is critical because business requirements drive the entire systems development effort.
waterfall methodology
a sequence of phases in which the output of each phase becomes the input for the next. in SDLC, this means the steps are performed one at a time, in order, from planning through implementation and maintenance.
agile methodology
aims for customer satisfaction through early and continuous delivery of useful software components developed by an iterative process using the bare minimum requirements. fast and efficient, with low costs and fewer features. using this methodology helps refine feasibility and supports the process for getting rapid feedback as functionality is introduced.
Legacy system
an old system that is fast approaching or beyond the end of its useful life within an organization
issues related to the waterfall methodology: the business problem
any flaws in accurately defining and articulating the business problem in terms of what the business users actually require flow onward to the next phase
project scope
describes the business need (the problem the project will solve) and the justification, requirements, and current boundaries for the projec
issues related to the waterfall methodology: the plan
managing costs, resources, and time constraints is difficult in the waterfall sequence. what happens to the schedule if a programmer quits? how will a schedule delay in a specific phase affect the total cost of the project? unexpected contingencies may sabotage the plan
planning phase
phase 1 establishes a high-level plan of the intended project and determines project goals. planning is the first and most critical phase of any systems development effort, regardless of whether the effort is to develop a system that allows customers to order products online, determine the best logistical structure for warehouses around the world, or develop a strategic information alliance with another organization
analysis phase
phase 2 the firm analyzes its end-user business requirements and refines project goals into defined functions and operations of the intended system
design phase
phase 3 establishes descriptions of the desired features and operations of the system, including screen layouts, business rules, process diagrams, pseudocodes, and other documentation.
development phase
phase 4 transforms all the detailed design documents from the design phase into the actual system. the project transitions from preliminary designs to actual physical implementation.
testing phase
phase 5 brings all the project pieces together into a special testing environment to eliminate errors and bugs and verify that the system meets all the business requirements defined in the analysis phase
implementation phase
phase 6 the organization places the system into production so users can begin to perform actual business operations with it
maintenance phase
phase 7 the organization performs changes, corrections, additions, and upgrades to ensure that the system continuous to meet business goals
SDLC phases
planning analysis design development testing implementation maintenance
project management
the application of knowledge, skills, tools, and techniques to project activities to meet project requirements
Systems development life cycle (SDLC)
the overall process for developing information systems, from planning and analysis through implementation and maintenance. the SDLC is the foundation for all systems development methods, and hundreds of activities are associated with each phase. these activities typically include determining budgets, gathering system requirements, and writing detail user documentation
issues related to the waterfall methodology: the solution
the waterfall methodology is problematic in that it assumes users can specify all business requirements in advance. defining the appropriate IT infrastructure that is flexible, scalable, and reliable is a challenge. the final IT infrastructure solution must meet not only current but also future needs in terms of time, cost, feasibility, and flexibility. vision is inevitably limited at the head of the waterfall