Hibernate many-to-many cascading delete

I found the correct mapping (and tested that with JUnit with an extensive case) in a similar scenario. I don't think I am going to post testing code because it would take long time to adapt to this example. Anyway the key is to:

• Not use mappedBy attribute for the annotations, use join columns
• List the possible CascadeTypes excluding REMOVE

In OP's example

@ManyToMany(fetch = FetchType.LAZY,
        cascade =
        {
                CascadeType.DETACH,
                CascadeType.MERGE,
                CascadeType.REFRESH,
                CascadeType.PERSIST
        },
        targetEntity = Course.class)
@JoinTable(name = "XTB_STUDENTS_COURSES",
        inverseJoinColumns = @JoinColumn(name = "COURSE_ID",
                nullable = false,
                updatable = false),
        joinColumns = @JoinColumn(name = "STUDENT_ID",
                nullable = false,
                updatable = false),
        foreignKey = @ForeignKey(ConstraintMode.CONSTRAINT),
        inverseForeignKey = @ForeignKey(ConstraintMode.CONSTRAINT))
private final Set<Course> courses = new HashSet<>();

@ManyToMany(fetch = FetchType.LAZY,
        cascade =
        {
                CascadeType.DETACH,
                CascadeType.MERGE,
                CascadeType.REFRESH,
                CascadeType.PERSIST
        },
        targetEntity = Student.class)
@JoinTable(name = "XTB_STUDENTS_COURSES",
        joinColumns = @JoinColumn(name = "COURSE_ID",
                nullable = false,
                updatable = false),
        inverseJoinColumns = @JoinColumn(name = "STUDENT_ID",
                nullable = false,
                updatable = false),
        foreignKey = @ForeignKey(ConstraintMode.CONSTRAINT),
        inverseForeignKey = @ForeignKey(ConstraintMode.CONSTRAINT))
private final Set<Student> students = new HashSet<>();

Extensive JUnit testing verified that:

• I can add courses to students and vice versa flawlessly
• If I remove a course from a student, the course is not deleted
• Vice versa
• If I remove a student, all courses are detached but they are still persisted (to other students) in database
• Vice versa

Based on what you've told me you don't want cascade=CascadeType.ALL on the getCourseses method in Student. Keep in mind that Hibernate cascades are not the same as database cascades. Even if you don't have any cascades then Hibernate will delete the Students_Courses record.

The best way to think of Hibernate cascades is that if you call an operation on an entity and that operation is listed in the cascade list then that operation will be called on all of the child entities.

For example, when you call delete on Student, since delete is in the cascade list for Courses, Hibernate will call delete on each of the Course entities referenced by that student. That is why you are seeing the Course records disappearing.

Don't worry about database cascades, Hibernate will take care of those on its own.

You just need to Remove cascade = CascadeType.ALL in Student class only no change is required in Courses class

and add the below code cascade = {CascadeType.PERSIST,CascadeType.MERGE,CascadeType.DETACH}..

It means while deleting owner class record it will not delete a non-owner record.

After this, On Delete it will delete only from Student table and student_course. course table data remains the same.