Entity Modeling Basics Quiz
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Questions and Answers

What is the main purpose of an entity in a database design?

  • To represent an object that will have many instances in the database (correct)
  • To represent a user of the database system
  • To represent an output of the database system, such as a report
  • To represent a concept that is not related to the database system
  • What is the difference between an entity type and an entity instance?

  • An entity type is a collection of entities with common attributes, while an entity instance is a single occurrence of an entity. (correct)
  • An entity type is a user of the database system, while an entity instance is an output of the database system.
  • An entity type is a single occurrence of an entity, while an entity instance is a collection of entities with common attributes.
  • An entity type is an abstract concept, while an entity instance is a physical object in the database.
  • What is the key difference between a strong entity and a weak entity?

  • A strong entity has a unique identifier, while a weak entity does not.
  • A strong entity is independent of other entities, while a weak entity is dependent on a strong entity.
  • A strong entity is represented by a single-line underlined identifier, while a weak entity is represented by a double-line underlined identifier.
  • All of the above (correct)
  • What is the purpose of an identifying relationship in a database design?

    <p>To link a weak entity to a strong entity</p> Signup and view all the answers

    What is the main purpose of defining relationships in a database design?

    <p>To represent the connections between entities in the database</p> Signup and view all the answers

    What is the purpose of modeling relationship types as lines between entity types?

    <p>To represent the specific instances of entities involved in a relationship</p> Signup and view all the answers

    When does a relationship turn into an associative entity?

    <p>When it has attributes and is a many-to-many relationship</p> Signup and view all the answers

    What does the degree of a relationship represent?

    <p>The number of entity types participating in the relationship</p> Signup and view all the answers

    If the minimum cardinality of a relationship is zero, what does it indicate?

    <p>The relationship is optional</p> Signup and view all the answers

    Which of the following statements about attributes is true?

    <p>Attributes can describe properties of both entity types and relationship types</p> Signup and view all the answers

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