Challenge – Part 2

There is an imbalance in the course_student relationship.

Launch the Starter Project

Task 1

Make 4 PUT requests:

localhost:8080/course/1/student/1
localhost:8080/course/5/student/1

localhost:8080/course/1/student/2
localhost:8080/course/6/student/2

Task 2

Delete the course with an ID of 5. It gets deleted in the course table.

Because course owns the association, associated records are deleted in the join table as well.

Now, try deleting the student with an id of 2.

{
    "timestamp": "08-08-2022 07:19:05",
    "message": [
        "Data Integrity Violation: we cannot process your request."
    ]
}

Ideally, deleting a student would also remove associated records in the join table.

But student is the non-owning side of the association, and cannot make changes to the join table.

Task 3

In order for student to be equal in managing the relationship, you need to:

1. Remove mappedBy.
2. Make sure that student owns the join table as well.

    @JoinTable(
        name = "course_student",
        joinColumns = @JoinColumn(name = "student_id", referencedColumnName = "id"),
        inverseJoinColumns = @JoinColumn(name = "course_id", referencedColumnName = "id")
    )

Task 4

Make 2 PUT requests:

localhost:8080/course/1/student/1
localhost:8080/course/1/student/2

Then delete the student with an id of 2.

Good Luck!