問49
頻出度★★★
システム開発を，システム要件定義，外部設計，内部設計，プログラミングの順で進めるとき，画面のレイアウトや帳票の様式を定義する工程として，最も適切なものはどれか。
平成25年度 春期 ITパスポート試験 問49
マネジメント系システム開発技術 › システム開発技術
This question's explanation and your answers so far.
解説
問 49
Incorrectア
System requirements definition is the process of clarifying, from the business side's viewpoint, what functions and performance the system needs — that is, “what to build”. It organizes the necessary information and the business requirements, but it does not yet decide concrete display and output forms such as screen layout or the format of reports.
- イ
正解 The correct answer is “イ External design”. External design is the process that turns the “what to realize” compiled in system requirements definition into a form visible to users (the external interface); it is also called functional design. Screen layout, the arrangement of input fields, the format of reports (output forms), the form of exchanges with other systems, and so on are all parts that users or the outside can see directly, so they are defined in external design. Within the process order given in the question, “system requirements definition → external design → internal design → programming”, external design is the stage that fixes the specification as seen from the user's side. The flow is to settle the format of screens and reports here, and only then move on to the internal way of realizing them (internal design).
Incorrectウ
Internal design, also called detailed design, is the process of designing from the developer's viewpoint how the external specification decided in external design will actually be realized. Its targets are the internal structure of the program, module division, how data is held, processing procedures, and so on; it is not the process that decides the format of screens and reports visible to users.
Incorrectエ
Programming is the process of writing (coding) the program exactly according to the specification decided in the design processes. Screen or report formats are not newly defined here; it only implements the design that has already been settled.
ここがポイント
- External design (functional design) = design of the parts visible to users. It is the process that defines “specifications visible from the outside”, such as screen layout, report formats, and input/output interfaces.
- Internal design (detailed design) = design of the parts visible to developers. It is the process that decides how to realize the specification settled in external design (internal structure, module division, processing procedures).
用語