如何在hibernate实体中通过多列定义索引？ [英] How to define index by several columns in hibernate entity?

问题描述

上午。

我需要在hibernate实体中添加索引。据我所知，可以使用@Index注释来为单独的列指定索引，但我需要一个实体的几个字段的索引。

我已经使用Google搜索并找到jboss注释@Table，允许这样做（按规范）。但是（我不知道为什么）这个功能不起作用。可能是jboss版本低于必要的，或者我不明白如何使用此注释，但是...复杂索引不会创建。

为什么index可能不会被创建？

JBoss 4.2.3.GA版本

实体示例：

  package somepackage; 
 import org.hibernate.annotations.Index; 
 
 import javax.persistence.Column; 
 import javax.persistence.Entity; 
 import javax.persistence.GeneratedValue; 
 import javax.persistence.Id; 
 
 @Entity 
 @ org.hibernate.annotations.Table（applicableTo = House.TABLE_NAME，
 indexes = {
 @Index（name =IDX_XDN_DFN，
 columnNames = {House.XDN，House.DFN} 
）
} 
）
 
 public class House {
 public final static String TABLE_NAME =房子; 
 public final static String XDN =xdn; 
 public final static String DFN =dfn; 
 
 @Id 
 @GeneratedValue 
私人长ID; 
 
 @Column（name = XDN）
私人长xdn; 
 
 @Column（name = DFN）
 private long dfn; 
 
 @Column 
私有字符串地址; 
 
 public long getId（）{
 return Id; 
} 
 
 public void setId（long id）{
 this.Id = id; 
} 
 
 public long getXdn（）{
 return xdn; 
} 
 
 public void setXdn（long xdn）{
 this.xdn = xdn; 
} 
 
 public long getDfn（）{
 return dfn; 
} 
 
 public void setDfn（long dfn）{
 this.dfn = dfn; 
} 
 
 public String getAddress（）{
 return address; 
} 
 
 public void setAddress（String address）{
 this.address = address; 
 
 
  

当jboss / hibernate尝试创建表house它抛出以下异常：

 原因：org.hibernate.AnnotationException：@ org.hibernate.annotations.Table引用未知表： house 
  

解决方案

请尝试以下操作：

  @Entity 
 @ org.hibernate.annotations.Table（applicableTo = House.TABLE_NAME，
 indexes = {
 @Index（name =IDX_XDN_DFN，
 columnNames = {House.XDN，House.DFN} 
）
} 
）
 @Table（name =房屋）
公共类房屋{
 ... 
} 
  

<请注意，这也应该允许您创建一个多列索引（基于索引名称）：

  @Index （name =index1）
 public String getFoo（）; 
 
 @Index（name =index1）
 public String getBar（）; 
  

P.S .:您使用的是BTW的哪个版本的Hibernate？什么数据库/方言？

Morning.

I need to add indexing in hibernate entity. As I know it is possible to do using @Index annotation to specify index for separate column but I need an index for several fields of entity.

I've googled and found jboss annotation @Table, that allows to do this (by specification). But (I don't know why) this functionality doesn't work. May be jboss version is lower than necessary, or maybe I don't understant how to use this annotation, but... complex index is not created.

Why index may not be created?

jboss version 4.2.3.GA

Entity example:

package somepackage;
import org.hibernate.annotations.Index;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

@Entity
@org.hibernate.annotations.Table(appliesTo = House.TABLE_NAME,
    indexes = {
            @Index(name = "IDX_XDN_DFN",
                    columnNames = {House.XDN, House.DFN}
            )
    }
)

public class House {
    public final static String TABLE_NAME = "house";
    public final static String XDN = "xdn";
    public final static String DFN = "dfn";

    @Id
    @GeneratedValue
    private long Id;

    @Column(name = XDN)
    private long xdn;

    @Column(name = DFN)
    private long dfn;

    @Column
    private String address;

    public long getId() {
        return Id;
    }

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

    public long getXdn() {
        return xdn;
    }

    public void setXdn(long xdn) {
        this.xdn = xdn;
    }

    public long getDfn() {
        return dfn;
    }

    public void setDfn(long dfn) {
        this.dfn = dfn;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

When jboss/hibernate tries to create table "house" it throws following exception:

Reason: org.hibernate.AnnotationException: @org.hibernate.annotations.Table references an unknown table: house

解决方案

Please try the following:

@Entity
@org.hibernate.annotations.Table(appliesTo = House.TABLE_NAME,
    indexes = {
            @Index(name = "IDX_XDN_DFN",
                    columnNames = {House.XDN, House.DFN}
            )
    }
)
@Table(name="house")
public class House {
    ...
}

Note that this should also allow you to create a multi-column index (based on the index name):

@Index(name = "index1")
public String getFoo();

@Index(name = "index1")
public String getBar();

P.S.: What version of Hibernate are you using BTW? What database/dialect?

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