我有一个表student和一个表course，它们被一个关联表student_course引用。这就是实体的样子

@Entity
public class Student {
    @Id
    @GeneratedValue(generator = "UUID")
    @GenericGenerator(
            name = "id",
            strategy = "com.something.UUIDGenerator"
    )
    private UUID id;
    @ManyToMany(cascade = { CascadeType.PERSIST, CascadeType.MERGE })
    @JoinTable(
            name = "student_course",
            joinColumns = @JoinColumn(name = "student_id"),
            inverseJoinColumns = @JoinColumn(name = "course_id")
    )
    private List<Course> courses;
    @OneToMany(mappedBy = "student")
    @OrderBy("sequenceNumber ASC")
    private List<StudentCourse> studentCourses;
}
@Entity
public class Course {
    @Id
    @GeneratedValue(generator = "UUID")
    @GenericGenerator(
            name = "id",
            strategy = "com.something.UUIDGenerator"
    )
    private UUID id;
    @ManyToMany(mappedBy = "students")
    private List<Student> students;
    @OneToMany(mappedBy = "course")
    @OrderBy("sequenceNumber ASC")
    private List<StudentCourses> studentCourses;
}
@Entity
public class StudentCourse {
    @EmbeddedId
    private StudentCourseId studentCourseId;
    @ManyToOne
    @MapsId("studentId")
    @JoinColumn(name = "student_id")
    private Student student;
    @ManyToOne
    @MapsId("courseId")
    @JoinColumn(name = "course_id")
    private Course course;
    private Long sequenceNumber;
}
@Embeddable
public class StudentCourseId implements Serializable {
    private UUID studentId;
    private UUID courseId;
}

我对表没有级联约束，我尝试用查询从student中删除记录，但在student_course中引用的记录没有删除。如果我使用StudentRepository的deleteById，那么在student_course中引用它们的记录也会被删除。我不想那样，我想处理删除。

@Repository
public interface StudentRepository extends CrudRepository<Student, UUID> {
}

你知道为什么会这样吗我不希望删除这两个表的记录时发生级联。
我正在使用PostgreSQL和spring-boot-starter-parent的2.3.3.RELEASE。