Question

Team和TeamMember属于ManyToMany关系。当我试图删除这样的团队时：

public void deleteTeam(int id) {
        Team team = (Team) getCurrentSession().get(Team.class, id);
        getCurrentSession().delete(team);
}

它给了：

org.springframework.dao.InvalidDataAccessApiUsageException: deleted object would be re-saved by cascade (remove deleted object from associations): [com.sprhib.model.Team#1]; 
    nested exception is org.hibernate.ObjectDeletedException: deleted object would be re-saved by cascade (remove deleted object from associations): [com.sprhib.model.Team#1]

然后我试图从持有我需要删除的团队的团队成员实体中删除所有团队：

public void deleteTeam(int id) {
        Team team = getTeam(id);
        if(team != null){
            for(TeamMember tm: team.getTeamMembers()){
                for(Team t: tm.getTeams()){
                    if(t.getId() == team.getId()){
                        tm.getTeams().remove(t);
                    }
                }
            }
            getCurrentSession().delete(team);
        }
    }

但同样的错误仍然存在。首先，我希望Hibernate能够相应地管理ManyToMany关系中的所有相关实体，因为它们具有注释。但它拒绝工作。 WTF？

团队

@Entity
@Table(name="teams")
public class Team {


    private int id;

    private String name;

    private int rating;

    private Set<TeamMember> teamMembers;

    private Organization organization;

    @Id
    @NotNull
    @GeneratedValue(strategy = GenerationType.AUTO)
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    @Length(max = 45)
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    @NotNull
    @Range(min = 0,max = 10)
    public int getRating() {
        return rating;
    }
    public void setRating(int rating) {
        this.rating = rating;
    }

    @NotNull
    @ManyToOne(fetch = FetchType.EAGER, cascade = {CascadeType.MERGE})
    @JoinColumn(name = "FK_Organization_id", nullable = false)
    public Organization getOrganization() {
        return organization;
    }

    public void setOrganization(Organization organization) {
        this.organization = organization;
    }

    @ManyToMany(fetch = FetchType.EAGER, cascade = {CascadeType.ALL})
    @JoinTable(name = "team_member", joinColumns =
        @JoinColumn(name = "FK_Team_id", referencedColumnName= "id"),
            inverseJoinColumns = @JoinColumn(name = "FK_Member_id", referencedColumnName = "id")
    )
    public Set<TeamMember> getTeamMembers() {
        return teamMembers;
    }

    public void setTeamMembers(Set<TeamMember> teamMembers) {
        this.teamMembers = teamMembers;
    }
}

TeamMember

@Entity
@Table(name="member")
public class TeamMember {

    private int id;

    private String name;

    private Set<Team> teams;

    @Id
    @NotNull
    @GeneratedValue(strategy = GenerationType.AUTO)
    public int getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }
    @NotEmpty
    @Length(max=100)
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @NotNull
    @ManyToMany(fetch = FetchType.EAGER, mappedBy = "teamMembers", cascade = {CascadeType.MERGE, CascadeType.PERSIST, CascadeType.REFRESH, CascadeType.REMOVE}) // cascade!!!
    public Set<Team> getTeams(){
        return teams;
    }

    public void setTeams(Set<Team> teams) {
        this.teams = teams;
    }


}

Answer 1

REMOVE不应与JPA 2.0规范中的@ManyToMany一起使用。

关系建模注释约束了cascade = REMOVE规范的使用。 cascade = REMOVE规范应仅应用于指定为OneToOne或OneToMany的关联。将cascade = REMOVE应用于其他关联的应用程序不可移植。

Hibernate中有供应商扩展@OnDelete：

@OnDelete（动作= OnDeleteAction.CASCADE）

在尝试删除ManyToMany关系中的实体时，Hibernate会抛出异常

1 个答案: