3. Quiz Questions
Prev Chapter 14. Bidirectional Associations Next

3. Quiz Questions

If you would like to look up the answers to the following quiz questions, you can check our discussion forum. If you don't find an answer in the forum, you may create a post asking for an answer to a particular question.

If you would like to do interactive quizzes with online feedback and with the option to ask a coach, then you should enrol in the advanced online course (book parts 4-5) offered by our partner developer-competence.com.

3.1. Question 1: Table populations of bidirectional associations

Consider the following table pairs representing the populations of the classes A and B where the columns A::id and B::id are primary keys and A::b_id and B::a_id are foreign keys referencing B, respectively A.

In which of the following cases does the property pair A::b_id and B::a_id implement a bidirectional association?

Select one:

  1. O

    AB
    idb_id
    1 2
    2 1
    3 3
    ida_id
    1 2
    2 1
    3 3

  2. O

    AB
    idb_id
    1 3
    2 1
    3 2
    ida_id
    1 1
    2 3
    3 2

  3. O

    A B
    id b_id
    1 3
    2 1
    3 2
    id a_id
    1 2
    2 3
    3 1

  4. O

    A B
    id b_id
    1 3
    2 3
    3 2
    id a_id
    1 2
    2 3
    3 1

3.2. Question 2: Implications of bi-directionality

Representing a bidirectional association with a pair of mutually inverse reference properties implies (select one or many):

  1. ☐ information redundancy

  2. ☐ slower read access

  3. ☐ data storage overhead

  4. ☐ update overhead

  5. ☐ faster updates

  6. ☐ more efficient data storage requiring less memory

  7. ☐ efficient object access in both directions

3.3. Question 3: Elimination of bi-directional associations

Consider the following information design model with a bidirectional association between the classes Aa and Bb.

Which of the following association-free models are correct representations of this model? (select one or many):

  1. ☐

  2. ☐

  3. ☐

  4. ☐

3.4. Question 4: Meaning of bi-directional association

A bidirectional association Committee-isChairedBy-ClubMember between the classes Committee and ClubMember corresponds to (select one or many):

  1. ☐ A pair of reference properties Committee::chair and ClubMember::chairedCommittee such that Committee::chair is the inverse of ClubMember::chairedCommittee and ClubMember::chairedCommittee is the inverse of Committee::chair.

  2. ☐ A pair of reference properties Committee::chair and ClubMember::chairedCommittee.

  3. ☐ A pair of reference properties Committee::chair and ClubMember::chairedCommittee such that Committee::chair is the inverse of ClubMember::chairedCommittee.

  4. ☐ A pair of reference properties Committee::chair and ClubMember::chairedCommittee such that ClubMember::chairedCommittee is the inverse of Committee::chair.

Prev Up Next
2. Making an Association-Free Information Design Model Home Chapter 15. Implementing Bidirectional Associations with Java, JPA and JSF