In the context of ER modeling, what does a 'weak entity' represent?
Practice Questions
1 question
Q1
In the context of ER modeling, what does a 'weak entity' represent?
An entity that cannot exist without a strong entity
An entity with no attributes
An entity that has a composite key
An entity that is not related to any other entity
A weak entity represents an entity that cannot exist without a strong entity, relying on it for its identification.
Questions & Step-by-step Solutions
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Q
Q: In the context of ER modeling, what does a 'weak entity' represent?
Solution: A weak entity represents an entity that cannot exist without a strong entity, relying on it for its identification.
Steps: 5
Step 1: Understand what an entity is. An entity is something that can be identified and has data associated with it, like a person or a car.
Step 2: Learn about strong entities. A strong entity can exist on its own and has a unique identifier, like an ID number.
Step 3: Know what a weak entity is. A weak entity is one that cannot be identified by its own attributes alone.
Step 4: Realize that a weak entity depends on a strong entity for its identification. It needs the strong entity's identifier to be recognized.
Step 5: Example: Think of a 'Room' as a weak entity that needs a 'Building' (strong entity) to be identified. A room number alone might not be unique without knowing which building it belongs to.
