Hibernate：如何删除没有级联的其他实体引用的实体？

Question

i've this two classes:

    @Entity
    @Table(name = "team")
    @Getter
    @Setter
    @NoArgsConstructor
    public class Team {

     @Id
     @GeneratedValue
     private Long id;

     private String name;

     @Enumerated(EnumType.STRING)
     private ProblemArea problemArea;


     @JsonIgnore
     @OneToMany(mappedBy = "team")
     @Cascade(value = org.hibernate.annotations.CascadeType.PERSIST)
     private List<TeamMember> teamMemberList;

     @JsonIgnore
     @OneToOne
     @Cascade(value = org.hibernate.annotations.CascadeType.PERSIST)
     private TeamLeader teamLeader;
   }


    @Entity
    @Table(name = "team_member")
    @Getter
    @Setter
    public class TeamMember extends InternalUser {

     @OneToOne
     @Cascade(value = org.hibernate.annotations.CascadeType.PERSIST)
     protected Team team;
    }

The problem is that when i try to DELETE a Team instance i got an error beacause of a Foreign key referenced on TeamMember table. How to DELETE Team instance correctly without deleting referenced TeamMember? This is the delete method inside TeamController:

        public boolean deleteTeam(@NotNull Long id) {
         if (!teamDao.existsById(id)) {
         return false;
         }
         teamDao.deleteById(id);
         return true;
        }

Answer 1

How to DELETE Team instance correctly without deleting referenced TeamMember?

1. First of all you have to find the Team Object
2. For each TeamMember of this Team set null to the Team
3. clear the List of Members from the Team
4. then remove the Team

The main idea is to break the relation between the Team Object and its Memebers

Your code can look like this :

public boolean deleteTeam(@NotNull Long id) {
    //Find the Team by its id
    Team team = teamDao.findById(id);   
    //If the team exist then    
    if (team != null) {                     
        for (TeamMember member : team.getTeamMemberList) {
            //Set null to Team for each Member(Brock the relation between father and sons)
            member.setTeam(null);           
        }
        //Make sure that the list of members are empry
        team.getTeamMemberList.clear();
        //then delete the team
        teamDao.deleteById(team.getId());
        return true;
    }
    //Else if the team is null return false
    return false;            
}