Recall & Review
beginner
What does a rectangle represent in an ER diagram?
A rectangle represents an Entity, which is a real-world object or concept that can have data stored about it.
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beginner
What symbol is used to represent an attribute in an ER diagram?
An ellipse (oval shape) is used to represent an attribute, which describes properties of an entity or relationship.
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beginner
How is a relationship shown in an ER diagram?
A diamond shape represents a relationship, showing how two or more entities are connected.
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intermediate
What does a double ellipse indicate in ER diagram notation?
A double ellipse represents a multivalued attribute, meaning the attribute can have multiple values for a single entity.
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intermediate
What is the meaning of a double rectangle in an ER diagram?
A double rectangle represents a weak entity, which depends on another entity (called the owner) for its identification.
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Which shape is used to represent an entity in an ER diagram?
✗ Incorrect
Entities are shown as rectangles in ER diagrams.
What does a diamond shape represent in an ER diagram?
✗ Incorrect
A diamond shape represents a relationship between entities.
In ER notation, what does a double ellipse indicate?
✗ Incorrect
A double ellipse shows a multivalued attribute.
Which symbol represents a weak entity in an ER diagram?
✗ Incorrect
Weak entities are shown with double rectangles.
What does an underline under an attribute name signify in ER diagrams?
✗ Incorrect
An underline indicates the attribute is a primary key.
Explain the main symbols used in ER diagram notation and what each represents.
Think about shapes and what real-world concepts they stand for.
You got /5 concepts.
Describe how you would identify a weak entity and a multivalued attribute in an ER diagram.
Look for double shapes.
You got /2 concepts.