Hibernate @OneToMany関係

Question

@OneToMany関係にいくつか問題があります。 最初のエンティティは何らかの種類の商品を表します。私は「AR_GROUPリストから選択リスト」のような選択作るとき

@Entity(name = "ARTIQULE") 
public final class ArtiquleEntity extends CustomEntity{ 

@Id 
@Column(name = "ID") 
public Long id; 

@NotNull 
@Column(name = "METRIC_ID") 
public Long metricId; 

@NotNull 
@Column(name = "STATUS_ID") 
public Long statusId; 

@NotNull 
@Column(name = "NAME") 
public String name; 

@NotNull 
@Column(name = "SHORT_NAME") 
public String shortName; 

@NotNull 
@ManyToOne 
@JoinColumn(name = "GROUP_ID") 
public ArtGroupEntity artGroup; 
} 

第二には、商品

@Entity(name = "AR_GROUP") 
public final class ArtGroupEntity extends CustomEntity { 

@Id 
@Column(name = "ID") 
public Long id; 

@NotNull 
@Column(name = "GROUP_ID") 
public Long groupId; 

@NotNull 
@Column(name = "STATUS_ID") 
public Long statusId; 

@NotNull 
@Column(name = "NAME") 
public String name; 

@NotNull 
@Column(name = "L") 
public Integer left; 

@NotNull 
@Column(name = "R") 
public Integer right; 

@NotNull 
@OneToMany(mappedBy = "artGroup", fetch = FetchType.EAGER) 
public List<ArtiquleEntity> artiquleEntities; 
} 

のグループ化されています。 グループごとにHibernateが選択を作成し、なぜ外部結合を使用しないのですか？ または可能ではありません。

Hibernate: select artgroupen0_.ID as ID1_0_, artgroupen0_.GROUP_ID as GROUP_ID2_0_, artgroupen0_.L as L3_0_, artgroupen0_.NAME as NAME4_0_, artgroupen0_.R as R5_0_, artgroupen0_.STATUS_ID as STATUS_I6_0_ from AR_GROUP artgroupen0_ 
Hibernate: select artiquleen0_.GROUP_ID as GROUP_ID2_1_0_, artiquleen0_.ID as ID1_1_0_, artiquleen0_.ID as ID1_1_1_, artiquleen0_.GROUP_ID as GROUP_ID2_1_1_, artiquleen0_.METRIC_ID as METRIC_I3_1_1_, artiquleen0_.NAME as NAME4_1_1_, artiquleen0_.SHORT_NAME as SHORT_NA5_1_1_, artiquleen0_.STATUS_ID as STATUS_I6_1_1_ from ARTIQULE artiquleen0_ where artiquleen0_.GROUP_ID=? 
Hibernate: select artiquleen0_.GROUP_ID as GROUP_ID2_1_0_, artiquleen0_.ID as ID1_1_0_, artiquleen0_.ID as ID1_1_1_, artiquleen0_.GROUP_ID as GROUP_ID2_1_1_, artiquleen0_.METRIC_ID as METRIC_I3_1_1_, artiquleen0_.NAME as NAME4_1_1_, artiquleen0_.SHORT_NAME as SHORT_NA5_1_1_, artiquleen0_.STATUS_ID as STATUS_I6_1_1_ from ARTIQULE artiquleen0_ where artiquleen0_.GROUP_ID=? 
Hibernate: select artiquleen0_.GROUP_ID as GROUP_ID2_1_0_, artiquleen0_.ID as ID1_1_0_, artiquleen0_.ID as ID1_1_1_, artiquleen0_.GROUP_ID as GROUP_ID2_1_1_, artiquleen0_.METRIC_ID as METRIC_I3_1_1_, artiquleen0_.NAME as NAME4_1_1_, artiquleen0_.SHORT_NAME as SHORT_NA5_1_1_, artiquleen0_.STATUS_ID as STATUS_I6_1_1_ from ARTIQULE artiquleen0_ where artiquleen0_.GROUP_ID=? 

お返事ありがとうございます。

Answer 1

複数の実行中のクエリは、n + 1の問題が原因である可能性があります。

JOIN FETCHを使用すると、親クエリとすべてのマップされた子エンティティを1つのクエリでフェッチできます。

チェックアウトthis同様の答え。 HQLフェッチ結合を使用することによって解決

Answer 2

問題、 この

from AR_GROUP list left outer join fetch list.artiqules