Hibernate参数注入里面的映射，可能吗？

I'm using Hibernate in many projets. Since time I've developped my projects including a translation table that containts text values in every language for every other tables that need it.

我在许多项目中使用Hibernate。从那时起,我开发了我的项目,包括一个转换表,其中包含每种语言的文本值,以及其他需要它的表。

Mapping file for the translation table

映射转换表的文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
  <class dynamic-insert="false" dynamic-update="false" mutable="true" name="com.spectotechnologies.website.common.helper.TranslationValue" optimistic-lock="version" polymorphism="implicit" select-before-update="false" table="common_translations">
    <id name="keyTranslation">
      <generator class="native"/>
    </id>
    <property name="keyLanguage"/>
    <property name="tableName"/>
    <property name="fieldName"/>
    <property name="keyRow"/>
    <property name="value"/>
  </class>
</hibernate-mapping>

Exemple of one object that need translation :

一个需要翻译的对象的例子:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
  <class dynamic-insert="false" dynamic-update="false" mutable="true" name="com.spectotechnologies.website.common.helper.Category" optimistic-lock="version" polymorphism="implicit" select-before-update="false" table="common_categories">
    <id name="keyCategory">
      <generator class="native"/>
    </id>
    <property name="keyParent"/>
    <property name="tag"/>
    <property name="name" insert="false" update="false"/>
    <property name="description" insert="false" update="false"/>
  </class>
</hibernate-mapping>

Currently, I use this kind of SQL query to load objects

目前,我使用这种SQL查询来加载对象

"SELECT" +
    " c.keyCategory," +
    " c.keyParent," +
    " c.tag," +
    " tn.value AS name," +
    " td.value AS description" +
" FROM common_categories c" +
// name
" LEFT JOIN common_translations tn" +
    " ON tn.tableName = 'common_categories'" +
    " AND tn.fieldName = 'name'" +
    " AND tn.keyRow = c.keyCategory" +
    " AND tn.keyLanguage = ?" +
// description
" LEFT JOIN common_translations td" +
    " ON td.tableName = 'common_categories'" +
    " AND td.fieldName = 'description'" +
    " AND td.keyRow = c.keyCategory" +
    " AND td.keyLanguage = ?" +
" ORDER BY" +
    " c.keyCategory ASC"

I was wondering if it is possible to transfer this kind of LEFT JOINS inside the mapping, for that I need to include parameters : tableName, fieldName, language.

我想知道是否有可能在映射中传输这种LEFT JOINS,因为我需要包含参数:tableName,fieldName,language。

Your help about that will be much appreciated, I'll be able to simplify a lot of queries!

非常感谢您对此的帮助,我将能够简化大量查询!

EDIT :

Here is an example of what I expect :

这是我期望的一个例子:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
  <class dynamic-insert="false" dynamic-update="false" mutable="true" name="com.spectotechnologies.website.common.helper.Category" optimistic-lock="version" polymorphism="implicit" select-before-update="false" table="common_categories">
    <id name="keyCategory">
      <generator class="native"/>
    </id>
    <property name="keyParent"/>
    <property name="tag"/>
    <one-to-many class="com.spectotechnologies.website.common.helper.TranslationValue"
  formula="tableName = 'common_categories' AND fieldName = 'name' AND keyLanguage = @language AND keyRow = keyCategory" name="name" />
    <one-to-many class="com.spectotechnologies.website.common.helper.TranslationValue"
  formula="tableName = 'common_categories' AND fieldName = 'description' AND keyLanguage = @language AND keyRow = keyCategory" name="description" />
  </class>
</hibernate-mapping>

In that case I would need to create a variable @language that could be injected at query time. There is two problems with this solution :

在这种情况下,我需要创建一个可以在查询时注入的变量@language。此解决方案存在两个问题:

I don't know if it is possible to publish a variable to mapping scope.

我不知道是否可以将变量发布到映射范围。
The formula is not existing for the moment : https://hibernate.onjira.com/browse/HHH-944

该公式暂时不存在:https://hibernate.onjira.com/browse/HHH-944

2 个解决方案

#1

For me all you need is to define one-to-many and many-to-one relation between the 2 entities. E.g. each category should have list (or set) of translations.

对我而言,您只需要定义2个实体之间的一对多和多对一关系。例如。每个类别都应该有翻译列表(或集合)。

#2

Since it was complicated to work with a table using a "custom key" (tableName and fieldName), I inverted the key. Now the Object needing multilingual text have a foreign key to the needed text. It only needs two tables for all multilingual data :

由于使用“自定义键”(tableName和fieldName)处理表很复杂,因此我将键反转。现在,需要多语言文本的对象具有所需文本的外键。所有多语言数据只需要两个表:

CREATE TABLE `common_multilingualtexts` (
  `keyMultilingualText` int(11) NOT NULL auto_increment,
  PRIMARY KEY  (`keyMultilingualText`)
) ENGINE=MyISAM AUTO_INCREMENT=0 DEFAULT CHARSET=utf8;

CREATE TABLE `common_multilingualtexts_values` (
  `languageCode` varchar(5) NOT NULL,
  `keyMultilingualText` int(11) NOT NULL,
  `value` text,
  PRIMARY KEY  (`languageCode`,`keyMultilingualText`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

The MultilingualText is now like this :

MultilingualText现在是这样的:

@Entity
@Table(name = "common_multilingualtexts")
public class MultilingualText implements Serializable
{
    private Integer m_iKeyMultilingualText;
    private Map<String, String> m_lValues = new HashMap<String, String>();

    public void setKeyMultilingualText(Integer p_iKeyMultilingualText)
    {
        m_iKeyMultilingualText = p_iKeyMultilingualText;
    }

    @Id
    @GeneratedValue
    @Column(name = "keyMultilingualText")
    public Integer getKeyMultilingualText()
    {
        return m_iKeyMultilingualText;
    }

    public void setValues(Map<String, String> p_lValues)
    {
        m_lValues = p_lValues;
    }

    @ElementCollection(fetch = FetchType.EAGER)
    @MapKeyColumn(name = "languageCode")
    @CollectionTable(name = "common_multilingualtexts_values", joinColumns = @JoinColumn(name = "keyMultilingualText"))
    @Column(name = "value")
    public Map<String, String> getValues()
    {
        return m_lValues;
    }

    public void put(String p_sLanguageCode, String p_sValue)
    {
        m_lValues.put(p_sLanguageCode,p_sValue);
    }

    public String get(String p_sLanguageCode)
    {
        if(m_lValues.containsKey(p_sLanguageCode))
        {
            return m_lValues.get(p_sLanguageCode);
        }

        return null;
    }
}

And each field that need to be multilingual simply need to be declared as follow :

每个需要多语言的字段只需要声明如下:

@OneToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "keyTitle")
public MultilingualText getTitle()
{
    return m_oTitle;
}

Note :

The only drawback is that each multilingual field generate a N + 1 select, I'll update my answer once I find a solution for that.

唯一的缺点是每个多语言字段都会产生N + 1选择,一旦找到解决方案,我就会更新我的答案。

#1