Hibernate不会删除OneToMany上的孤立项
我有以下非常简单的一对多关系: 球队有一组球员:Hibernate不会删除OneToMany上的孤立项,hibernate,jpa-2.0,hibernate-mapping,Hibernate,Jpa 2.0,Hibernate Mapping,我有以下非常简单的一对多关系: 球队有一组球员: @Entity(name = "TEAM") @Access(AccessType.PROPERTY) public class Team{ private Integer id; private String name; private Set<Player> players ; @Id @Column(name = "id") public Integer getId() {
@Entity(name = "TEAM")
@Access(AccessType.PROPERTY)
public class Team{
private Integer id;
private String name;
private Set<Player> players ;
@Id
@Column(name = "id")
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
@Column(name = "team_name")
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@OneToMany(cascade = {CascadeType.ALL},orphanRemoval=true)
@JoinColumn(name = "TEAM_ID")
public Set<Player> getPlayers() {
return players;
}
public void setPlayers(Set<Player> players) {
this.players = players;
}
}
我运行一个非常简单的代码:
Team team = createTeam(3) // creates team with 3 players ids={1,2,3}
session.saveOrUpdate(team);
...
private Team createTeam(int players) {
Team team = new Team();
team.setName("Bears");
team.setId(1);
for(int i=1 ; i<=players; ++ i){
Player player = new Player();
player.setId(i);
player.setName("Player"+i);
team.addPlayer(player);
}
return team;
}
希望孤儿玩家被删除,但我得到:
- 休眠:从team team_uuwhere team_uu.id=
- 休眠:从player player_uuwhere player_u.id=?中选择player_u.id,player_u.player_uname作为player2_1_u
- 休眠:从player player_uuwhere player_u.id=?中选择player_u.id,player_u.player_uname作为player2_1_u
- Hibernate:更新玩家集TEAM_ID=null,其中TEAM_ID=
- Hibernate:更新玩家集TEAM_ID=?其中id=
- Hibernate:更新玩家集TEAM_ID=?其中id=
知道我做错了什么吗?在两个实体的关系中添加mappedBy属性 在玩家中添加团队
// in Player.java
@ManyToOne(mappedBy="players")
private Team team;
//In Team.java
@OneToMany(cascade = {CascadeType.ALL},orphanRemoval=true,mappedBy="team")
@JoinColumn(name = "TEAM_ID")
public Set<Player> getPlayers() {
return players;
}
在播放器中使用MappeedBy
// in Player.java
@ManyToOne(mappedBy="players")
private Team team;
//In Team.java
@OneToMany(cascade = {CascadeType.ALL},orphanRemoval=true,mappedBy="team")
@JoinColumn(name = "TEAM_ID")
public Set<Player> getPlayers() {
return players;
}
如果希望将玩家作为删除孤立对象删除,则需要玩家释放对团队的引用并保存团队 您正在执行的操作如下:
- 创建一个新的对象团队
- 为球队提供3名队员
- 坚持
private Team createTeam(int players) {
Team team = session.get(Team.class, 1);
if (team == null) {
team = new Team();
team.setName("Bears");
team.setId(1);
}
team.clearPlayers();
for(int i=1 ; i<=players; ++ i){
Player player = new Player();
player.setId(i);
player.setName("Player"+i);
team.addPlayer(player);
}
return team;
}
// Team.java
private void clearPlayers() {
players.clear();
}
此外,集合是可变的,因此使用getPlayers()返回不可修改的集合:
private Set<Player> getPlayers() {
return Collections.unmodifiableSet(players);
}
private Set getPlayers(){
返回集合。不可修改集合(玩家);
}
希望这能给你一些启示:)你可以使用这个标签:
@org.hibernate.annotations.Cascade(value=org.hibernate.annotations.CascadeType.DELETE\u孤儿)。所以你得到:
@OneToMany(cascade={CascadeType.ALL},orphanRemoving=true)
@org.hibernate.annotations.Cascade(value=org.hibernate.annotations.CascadeType.DELETE\u孤儿)
@JoinColumn(name=“TEAM_ID”)什么是
createTeam()
方法?它可能是相关的,也可能不是,但是我们在HSQLOK上测试它,但是我们可以看到createTeam()
中的代码吗?刚刚用createTeam()更新了代码示例,没有理由使关联双向。无论如何,在双向关联中,只有一个边必须具有mappedBy属性,因为它的意思是:“查看另一端关联的映射”。
private void adddPlayer(Player player) {
player.setTeam(this);
players.add(player);
}
private void removePlayer(Player player) {
player.setTeam(null);
players.remove(player);
}
private Set<Player> getPlayers() {
return Collections.unmodifiableSet(players);
}