从带有嵌入ID的休眠查询返回的空列表 [英] Null list returned from hibernate query with embedded id

问题描述

我有一个嵌入式密钥的实体。实体只有键作为字段，键有7个字段，其中一些可以为空。

I have an entity with an embedded key. The entity has only the key as a field and the key has 7 fields, some of which can be null.

当我运行以下查询时：

Criteria criteria = session.createCriteria(getPersistentClass());
criteria.add(Restrictions.eq("id.profPropertyId", profileExtensionName));
Object obj = criteria.list();
log.info(obj);
return (List<ProfileExtensions>) obj; 

我得到正确数量的结果，但每个结果都为空（即，我得到一个4000空对象）。我曾尝试使用HQL查询和条件，但它们都给出了相同的结果。

I get the correct number of results, but each result is null (i.e. I get a list of 4000 null objects). I have tried using both a HQL query and criteria but they both give the same result.

映射类是从现有数据库生成的。

The mapping classes were generated from an existing database.

为查询生成的SQL如下所示：

The SQL generated for the query is as follows

select this_.PROF_DATA_TYPE as PROF1_14_0_, this_.PROF_EXT_KEY as PROF2_14_0_, 
       this_.PROF_KEY as PROF3_14_0_, this_.PROF_NAME as PROF4_14_0_, 
       this_.PROF_PROPERTY_ID as PROF5_14_0_, this_.PROF_VALUE as PROF6_14_0_, 
       this_.PROF_VALUE_EXTENDED as PROF7_14_0_ 
from EMPINST.PROFILE_EXTENSIONS this_ 
where this_.PROF_PROPERTY_ID=?

看起来它应该返回正确的数据。

Looks like it should return the correct data.

映射文件非常简单（并且从模式生成）：

The mapping file is pretty simple (and generated from the schema:

// Generated Oct 18, 2010 11:08:08 PM by Hibernate Tools 3.2.2.GA
import javax.persistence.AttributeOverride;
import javax.persistence.AttributeOverrides;
import javax.persistence.Column;
import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
import javax.persistence.Table;
import javax.persistence.UniqueConstraint;

@Entity
@Table(name="PROFILE_EXTENSIONS"
    ,schema="EMPINST"
    , uniqueConstraints = @UniqueConstraint(columnNames={"PROF_KEY", "PROF_PROPERTY_ID"}) )
public class ProfileExtensions  implements java.io.Serializable {


 private ProfileExtensionsId id;

public ProfileExtensions() {
}

public ProfileExtensions(ProfileExtensionsId id) {
   this.id = id;
}

 @EmbeddedId

@AttributeOverrides( {
    @AttributeOverride(name="profKey", column=@Column(name="PROF_KEY", nullable=false, length=36) ), 
    @AttributeOverride(name="profPropertyId", column=@Column(name="PROF_PROPERTY_ID", nullable=false, length=64) ), 
    @AttributeOverride(name="profExtKey", column=@Column(name="PROF_EXT_KEY", length=256) ), 
    @AttributeOverride(name="profName", column=@Column(name="PROF_NAME", length=256) ), 
    @AttributeOverride(name="profDataType", column=@Column(name="PROF_DATA_TYPE", length=64) ), 
    @AttributeOverride(name="profValue", column=@Column(name="PROF_VALUE", length=1024) ), 
    @AttributeOverride(name="profValueExtended", column=@Column(name="PROF_VALUE_EXTENDED") ) } )
  public ProfileExtensionsId getId() {
    return this.id;
  }

  public void setId(ProfileExtensionsId id) {
      this.id = id;
  }
}

推荐答案

一般来说，将可为空的列作为组合ID的一部分可能不是一个好主意。在我的情况下，它是必需的，因为我有一个使用外连接创建的视图，并且我遇到了与您所描述的完全相同的问题。我能够使用 https://hibernate.atlassian.net/browse/上提供的信息来解决此问题HHH-1109 。我使用附件中提供的NullableStringType来访问这个Hibernate Jira。在我使用的复合id类中：

In general it's probably not a good idea to have nullable columns as a part of composite id. In my case it was required because I had a view created using outer join and I faced exactly the same problem as you described. I was able to solve it using information provided on https://hibernate.atlassian.net/browse/HHH-1109. I used NullableStringType provided in the attachment to this Hibernate Jira. In my composite id class I used:

@Type(type = "nl.pinkroccade.quarant.common.model.hibernate.type.NullableStringType")
private String nullableField;

这篇关于从带有嵌入ID的休眠查询返回的空列表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！