Questions and Answers
Which of the following is NOT a component of an ER diagram?
In an ER diagram, a diamond shape typically represents:
What does a rectangle represent in an ER diagram?
Which type of relationship is represented by a line connecting two entities with a diamond in between?
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In an ER diagram, which of the following denotes a derived attribute?
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What is the main purpose of an ER diagram?
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Which of the following is NOT a component of an ER diagram?
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In an ER diagram, a diamond shape typically represents:
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Which symbol is used to represent a weak entity in an ER diagram?
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What does a rectangle represent in an ER diagram?
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Which of the following best describes a primary key in an ER diagram?
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In an ER diagram, an ellipse represents:
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Which type of relationship is represented by a line connecting two entities with a diamond in between?
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What is the main purpose of an ER diagram?
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Study Notes
ER Diagram Components
- Components of an ER diagram include entities, relationships, and attributes.
- Tables are NOT considered a component of an ER diagram.
Symbols in ER Diagrams
- A diamond shape represents a relationship between entities.
- A rectangle signifies an entity within the diagram.
- An ellipse is used to denote attributes of entities.
- A double rectangle symbolizes a weak entity.
- A dashed ellipse indicates a derived attribute.
Primary Keys and Attributes
- A primary key is defined as an attribute that uniquely identifies each entity within a table.
- Attributes can have different characteristics; they can be optional or have multiple values.
Types of Relationships
- Relationships can vary; one type involves a many-to-many connection noted by a line linking two entities with a diamond in between.
- Cardinality refers to the quantitative relationship between entities, specifying how many instances of one entity are linked to instances of another.
Purpose of ER Diagrams
- The primary purpose of an ER diagram is to represent the logical structure of a database, aiding in visualizing data relationships and organization.
- They help in the conceptual design of databases before implementation.
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Description
This quiz covers the essential components of Entity-Relationship (ER) diagrams, including symbols, primary keys, and types of relationships. Dive into the world of data modeling with questions on how these elements interact and function within database design.
