openjpa：多对多，带有额外的列

Posted 2023-04-19

【中文标题】openjpa：多对多，带有额外的列

【英文标题】：openjpa: many to many with extra column

【发布时间】：2012-03-04 19:42:53

【问题描述】：

我需要在 JPA 中创建一个带有额外列的多对多可连接。

我正在使用：openjpa-maven-plugin 在构建期间进行增强，openjpa 2.2.0，hsql file db，testng + spring

我有三个表：Analysis、localizedAnalysisName（可连接）和Locale

我的代码：

@Entity 
@Table(name = "analysis", catalog = "testdb") 
public class Analysis  
    @Id 
    @GeneratedValue(strategy = GenerationType.IDENTITY) 
    @Column(name = "analysis_id", unique = true, nullable = false) 
    private int analysisId; 

    @OneToMany(mappedBy = "analysis", cascade = CascadeType.PERSIST) 
    private List<LocalizedAnalysisName> localizedNames = new ArrayList<LocalizedAnalysisName>(); 

 public void addLocalizedName(Locale locale, String localized_text)  
        LocalizedAnalysisName localizedAnalysisName = new LocalizedAnalysisName(); 
        localizedAnalysisName.setLocale(locale); 
        localizedAnalysisName.setAnalysis(Analysis.this); 
        localizedAnalysisName.setLocaleId(locale.getLocaleId()); 
        localizedAnalysisName.setAnalysisId(this.getAnalysisId()); 
        localizedAnalysisName.setLocalizedText(localized_text); 

        localizedNames.add(localizedAnalysisName); 

     
    ... 


@Entity
@Table(name = "locale", catalog = "testdb")
public class Locale implements Serializable 
    @Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "locale_id", unique = true, nullable = false)
    private int localeId;
    @Column(name = "language", length = 200)
    private String language;
    @Column(name = "country", length = 200)
    private String country;
    @Column(name = "variant", length = 200)
    private String variant;

... 

@Entity
@Table(name = "localized_analysis_name", catalog = "testdb")
@IdClass(LocalizedAnalysisNameId.class)
public class LocalizedAnalysisName implements Serializable 
    @Id
    private int analysis_id;
    @Id
    private int locale_id;

    @Column(name = "localized_text", nullable = false, length = 200)
    private String localizedText;

    @ManyToOne
    @PrimaryKeyJoinColumn(name="locale_id", referencedColumnName="locale_id")
    private Locale locale;

    @ManyToOne
    @PrimaryKeyJoinColumn(name="analysis_id", referencedColumnName="analysis_id")
    private Analysis analysis;

    public LocalizedAnalysisName() 
    

    public String getLocalizedText() 
        return localizedText;
    

    public void setLocalizedText(String localizedText) 
        this.localizedText = localizedText;
    

    public Locale getLocale() 
        return locale;
    

    public Analysis getAnalysis() 
        return analysis;
    

    public void setLocale(Locale locale) 
        this.locale = locale;
    

    public void setAnalysis(Analysis analysis) 
        this.analysis = analysis;
    

    public void setAnalysisId(int analysis_id) 
        this.analysis_id = analysis_id;
    

    public void setLocaleId(int locale_id) 
        this.locale_id = locale_id;
    


@Embeddable
public class LocalizedAnalysisNameId implements Serializable 
    private int analysis_id;
    private int locale_id;

    public LocalizedAnalysisNameId() 
    

    public int getAnalysisId() 
        return analysis_id;
    

    public void setAnalysisId(int analysis_id) 
        this.analysis_id = analysis_id;
    

    public int getLocaleId() 
        return locale_id;
    

    public void setLocaleId(int locale_id) 
        this.locale_id = locale_id;
    

    public int hashCode() 
        return analysis_id + locale_id;
    

    public boolean equals(Object object) 
        if (object instanceof LocalizedAnalysisNameId) 
            LocalizedAnalysisNameId otherId = (LocalizedAnalysisNameId) object;
            return (otherId.analysis_id == this.analysis_id) && (otherId.locale_id == this.locale_id);
        
        return false;
    

数据库：

CREATE  TABLE locale (
  locale_id integer  NOT NULL IDENTITY,
  language varchar(200) DEFAULT NULL,
  country varchar(200) DEFAULT NULL,
  variant varchar(200) DEFAULT NULL,
  PRIMARY KEY (locale_id)
  );

CREATE TABLE  analysis (
  analysis_id integer NOT NULL IDENTITY,
  source_id varchar(500) DEFAULT NULL,
  locale_id integer,
  PRIMARY KEY (analysis_id),
  FOREIGN KEY (locale_id)
  REFERENCES locale (locale_id)
);


CREATE  TABLE localized_analysis_name (
  analysis_id integer,
  locale_id integer,
  localized_text varchar(200) DEFAULT NULL,
  PRIMARY KEY (analysis_id, locale_id),
  FOREIGN KEY (analysis_id)
  REFERENCES analysis (analysis_id),
   FOREIGN KEY (locale_id)
  REFERENCES locale (locale_id)
  );

INSERT INTO LOCALE VALUES(0,'en','US','');
INSERT INTO LOCALE VALUES(1,'de','DE','');

这是我在 testng 中的测试方法片段：

@Test(enabled = true) 
    @Rollback(false) 
    public void testSave()  

        Analysis analysis = new Analysis(); 

        Locale locale = localeDao.findById(0); 

        analysis.addLocalizedName(locale,"localized text"); 

        analysisDao.save(analysis); 

     

当我构建时，测试失败

invalidstateexception:  
Caused by: <openjpa-2.2.0-r422266:1244990 fatal user error> org.apache.openjpa.persistence.InvalidStateException:  
Attempt to set column "localized_analysis_name.analysis_id" to two different values: (class java.lang.Long)"0", (class java.lang.Integer)"40"  

This can occur when you fail to set both sides of a
two-sided relation between objects, or when you map
different fields to the same column, but you do not
keep the values of these fields in synch.

请谁能告诉我如何以正确的方式做到这一点？ 谢谢。

【参考方案1】：

不要在LocalizedAnalysisName 表中同时设置ID 和键引用。您正在将它们设置为不同的值：

// The test:
Analysis analysis = new Analysis(); 
Locale locale = localeDao.findById(0); 
analysis.addLocalizedName(locale,"localized text"); 

// The entity:
localizedAnalysisName.setLocale(locale); 
localizedAnalysisName.setAnalysis(Analysis.this); 
localizedAnalysisName.setLocaleId(locale.getLocaleId()); 
localizedAnalysisName.setAnalysisId(this.getAnalysisId()); 

当您调用setAnalysisId(...) 时，它处于“new”状态，还没有id（默认为0）。同时，您在 L.A.N. 上设置 Analysis 实体，实体管理器将为它分配一个新的 id。因此，L.A.N.同时拥有Analysis记录的2个不同id。

附带说明，LocalizedAnalysisNameId 上的 @Embeddable 注释不是必需的，因为您不将其用作 @EmbeddedId，而是直接列出其字段。

【讨论】：

现在的问题是如何在LocalizedAnalysisNameId类中设置analyis_id

我会设置 (locale_id, analysis_id) 或 (Locale, Analysis)，但不能同时设置。或者先坚持Analysis（并刷新），然后设置所有字段。