Transformation of N:N Relationship: Intersection vs. Association Tables
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Questions and Answers

What is a relation in the context of a Relational DBMS?

  • A three-dimensional table
  • A one-dimensional table
  • A two-dimensional table (correct)
  • A four-dimensional table

    • In a relation, what do columns typically contain?

  • Data about entities
  • Data about relationships
  • Data about attributes of the entities (correct)
  • Data about the database structure

    • What is a characteristic of entries in a column in a relation?

  • They are of the same kind (correct)
  • They are of different kinds
  • They are multivalued
  • They are unordered

    • How many primary keys can a relation have according to the text?

    <p>One</p> Signup and view all the answers

    What is the purpose of candidate keys in a relation?

    <p>To identify rows uniquely</p> Signup and view all the answers

    Which of the following is NOT a characteristic of relations in a Relational DBMS?

    <p>There can be multivalued attributes</p> Signup and view all the answers

    What is the solid line connecting an I D-dependent entity and its parent called?

    <p>Identifying relationship</p> Signup and view all the answers

    Which type of entity is considered weak?

    <p>ID-Dependent entity</p> Signup and view all the answers

    What is a weak entity in data modeling?

    <p>An entity whose existence depends on another entity</p> Signup and view all the answers

    Which type of relationship is used to represent ID-Dependent entities?

    <p>Identifying relationship</p> Signup and view all the answers

    What is the dashed line connecting strong entities or non-ID-dependent weak entities to their parent called?

    <p>Nonidentifying relationship</p> Signup and view all the answers

    How are weak entities that are not ID-Dependent represented in data modeling tools?

    <p>With nonidentifying relationships</p> Signup and view all the answers

    What is the purpose of an intersection table in a N:M relationship between strong entities?

    <p>To hold the relationships between two strong entities</p> Signup and view all the answers

    In an association table, what additional feature does it have compared to an intersection table?

    <p>It includes attributes specific to the associations of the other two entities</p> Signup and view all the answers

    What occurs in a cascading update between a parent and child in a database?

    <p>Child's primary key changes when parent's primary key changes</p> Signup and view all the answers

    When is cascading delete generally applied for strong entities?

    <p>Always</p> Signup and view all the answers

    What type of entities do not require cascading updates when changes are made?

    <p>Surrogate key-dependent entities</p> Signup and view all the answers

    What does an intersection table hold in a N:M relationship?

    <p>Only the primary keys of the two entities</p> Signup and view all the answers

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