リレーションシップで考慮すべきもう1つの側面は、子テーブルのいくつのレコードが、親テーブルの1つのレコードに紐付けられるかということである。 CUSTOMER とCUSTOMER_ORDER テーブルを例にとると、1対多のリレーションシップで、1つの顧客レコードが複数の注文に紐づくことがわかる。CUSTOMER_ID 3 の顧客 "Re-Barre Construction "は3つの注文と結びついている。
図8-4. CUSTOMER と ...
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