我已经做了3个多小时了，没有进展。我有这个方法：

public String deleteShift(Shifts shifts){
     Shifts shiftToBeDeleted = shiftsRepository.findById(shifts.getId()).orElseThrow(() ->new ShiftNotFoundException("This shift doesn't exist"));
           Set<Staff> staffListForShift = shiftToBeDeleted.getStaff();
  if (shiftToBeDeleted.getStaff().isEmpty()){
         System.out.println("this fucker:" + shiftToBeDeleted.getStaff());
         shiftsRepository.deleteById(shifts.getId());
         return "Shift removed.";
     }else {
         for (Staff staff : shiftToBeDeleted.getStaff()){
             System.out.println("this fucker is second:"+ staff.getUsername());
             staff.getShifts().remove(shiftToBeDeleted);
             staffRepository.save(staff);
         }
         shiftsRepository.deleteById(shiftToBeDeleted.getId());
         return "Shift removed, assign the free staff to a different one.";
     }
}

字符串
它应该删除一个移位，但它不断返回一个违反外键约束的，我不能为我的生活修复。
这是轮班课程

public class Shifts {
@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE)
private Long id;
@Temporal(TemporalType.TIME)
private LocalTime shiftStart;
@Temporal(TemporalType.TIME)
private LocalTime shiftEnd;
@ManyToMany(cascade = {CascadeType.PERSIST, CascadeType.MERGE, CascadeType.REFRESH})
@JsonIgnore
private Set<Staff> staff;}

型
这是staff类：

public class Staff {
@Id
private Long id;
private String username;
private String password;
@Enumerated(EnumType.STRING)
private StaffStates state;
@Enumerated(EnumType.STRING)
private UserTypes type;
@OneToOne( cascade = CascadeType.ALL)
@MapsId
@JoinColumn(name = "id")
private User user;
@OneToMany(cascade = CascadeType.ALL)
@JoinColumn(name = "staff")
private Set<WorkHours> workHoursSet;
@ManyToMany(cascade = {CascadeType.PERSIST, CascadeType.MERGE, CascadeType.REFRESH})
@JoinTable(
        name = "StaffShifts",
        joinColumns = @JoinColumn(name = "staffId"),
        inverseJoinColumns = @JoinColumn(name = "shiftId"))
private Set<Shifts> shifts;
@ManyToMany(cascade = {CascadeType.PERSIST, CascadeType.MERGE, CascadeType.REFRESH})
@JoinTable(
        name = "StaffPermissions",
        joinColumns = @JoinColumn(name = "staffid"),
        inverseJoinColumns = @JoinColumn(name = "permissionId"))
        private Set<Permissions> permissions;
@OneToMany()
private Set<Transactions> transactionsSet;

型
}
我尝试使用cascade来解决这个问题，但根据this，不建议删除cascade
编辑：错误在getStaff.isEMpty（）中。不知何故，检查中的人员列表弹出为空，但当我从中删除时，它抛出了一个违反外键的异常。