問52
頻出度★★★
関係データベースを構築するための作業を, a～c に分けて行うとき, 作業の順序として適切なものはどれか。 a 業務で使用するデータ項目の洗い出し b 表の生成 c レコードの挿入
平成27年度 秋期 ITパスポート試験 問52
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 52
- ア
正解 Building a relational database proceeds in the order “design → definition → loading data.” First, in a “Identifying the data items used in the business,” you analyze and design which data (items) to manage. Next, in b “Creating the table,” you use a statement such as CREATE to define the table structure, with the identified items as columns. Finally, in c “Inserting records,” you register the actual data row by row into the created table. Records cannot be added without an empty container (a table), and a table cannot be created until you decide what to handle (the items), so the order a → b → c is correct. Therefore “ア” is the correct answer.
Incorrectイ
a → c → b would perform c “Inserting records” before creating the table (b), which is impossible. A record is a row inside the container called a table, so it cannot be inserted when no table exists. The order is reversed, so this is wrong.
Incorrectウ
b → a → c would perform b “Creating the table” before finishing identifying the data items (a). If the items to be managed are not fixed, you cannot decide which columns the table should have, so the table cannot be defined. This skips the design step, so it is wrong.
Incorrectエ
b → c → a places the identification (a) last and performs the design only after creating the table (b) and inserting records (c), so the steps are completely reversed. The analysis of data items, which should be the most upstream step, is placed last, so it is wrong.
ここがポイント
- The basic steps of building a relational database follow the order “identifying data items (analysis and design) → creating the table (definition) → inserting records (loading data).”
- A record is a row inside the container called a table, so it can only be inserted after the table has been created. If the upstream step (what to manage) is not decided, you cannot move on to the downstream steps (the table and its data).
用語