問84
頻出度★★★
データベースを設計するときに, データの関連を整理して表現することを目的として使われるものはどれか。
平成28年度 春期 ITパスポート試験 問84
テクノロジ系データベース › データベース設計
This question's explanation and your answers so far.
解説
問 84
- ア
正解 The correct answer is (ア), the E-R Diagram. An E-R Diagram (Entity-Relationship Diagram) is a notation that treats the things to be managed as ‘entities’ and connects entities with lines to represent the ‘relationships’ between them. Entities map to tables and relationships map to links such as foreign keys, so it fits exactly the purpose of organizing and representing the data structure and the relationships among data when designing a database. Therefore, the tool used to organize and represent data relationships, as the question asks, is the E-R Diagram.
Incorrectイ
An arrow diagram (PERT chart) represents activities with arrows and nodes, and is used to draw up a schedule or find the critical path from the order and duration of the activities. It is used for project scheduling and process management, not for representing the relationships among data.
Incorrectウ
A Gantt chart lists activities (tasks) vertically and time horizontally, showing the start, end, and progress of each activity as horizontal bars. It is used for schedule and progress management, and has nothing to do with representing the relationships among data in database design.
Incorrectエ
A flowchart is a notation that connects symbols to represent the steps of processing or the control flow (sequence, branching, and looping). It is used to represent the processing flow of a program, algorithm, or business procedure, not to organize the relationship structure of the data itself.
ここがポイント
- An E-R Diagram represents data structure using ‘entities’ and ‘relationships’, and is a representative modeling technique in the conceptual design of a database.
- Distinguish the purpose of each notation: E-R Diagram = data relationships, arrow diagram = scheduling and process order, Gantt chart = progress and schedule, flowchart = processing flow.
用語