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A weak entity in an ER diagram is connected to its owner through
Aa regular single-diamond relationship
Ba foreign key on the strong entity
Ca partial-key attribute, drawn as a dashed ellipse
Dan identifying relationship, drawn as a double diamond
Answer & Solution
Correct answer: D. an identifying relationship, drawn as a double diamond
The identifying relationship is the bridge that gives a weak entity its identity; without it the weak entity has no way to be uniquely named. NPTEL's notation: double diamond. A partial key is an attribute on the weak entity, not the bridge; foreign keys are a relational concept, not ER.
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