Lifecycle Methodologies Vòng đời của một ứng dụng bao gồm toàn bộ sự tồn tại của nó, bắt đầu với một ý tưởng mơ hồ hình thành và kéo dài thông qua thiết kế, triển khai, phát triển và sử dụng của khách hàng. Các vòng đời có thể bao gồm bất kỳ số lượng các phiên bản và phiên bản mới, và kết thúc khi bản sao cuối cùng của ứng dụng là không còn được sử dụng và toàn bộ điều là xuống hạng với lịch sử. Một vòng đời của ứng dụng có thể kéo dài. | 5 I Lifecycle Methodologies An application s lifecycle covers its entire existence starting with a vaguely formed idea and lasting through design development deployment and use by customers. The lifecycle may include any number of revisions and new releases and ends when the last copy of the application is no longer used and the whole thing is relegated to history. An application s lifecycle may last 30 years and span dozens of releases and enhancements or it may be cut short during design when developers decide the application is impractical or doesn t adequately meet customer needs. Whether an application is intended to last a month a year or indefinitely you need to manage its lifecycle. For a simple one-use throwaway application you may spend very little time in lifecycle management. For longer-lived applications you may need to spend considerable effort to ensure that the application moves as smoothly as possible from the idea stage to a usable product and that it remains usable as long as possible or at least as long as it is needed. This chapter describes several different lifecycle methodologies that you can use to manage different kinds of applications. It discusses the strengths and weaknesses of each method and explains which work best when developing in Visual Basic. Lifecycle Stages All lifecycle strategies use the same fundamental stages arranged in various ways. In one approach some stages may be made longer or shorter. In another approach some stages may be reduced practically to the point of non-existence whereas others are repeated several times. Often different stages blur together with one overlapping another. However every approach uses the same basic stages to one extent or another. The following sections describe these basic stages. Part I Design Idea Formulation and Refinement Every application begins as an idea. Someone gets a notion about some program that might be useful. Sometimes the idea is only a vague notion such as Wouldn t it be .
