如何通过休眠实体中的几列定义索引? [英] How to define index by several columns in hibernate entity?

问题描述

早上好.

我需要在休眠实体中添加索引.据我所知，可以使用 @Index 批注为单独的列指定索引，但我需要为实体的多个字段设置索引.

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.

我在谷歌上搜索并找到了 jboss 注释@Table，它允许执行此操作(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，或者我可能不了解如何使用此注释，但是......没有创建复杂的索引.

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.

为什么不能创建索引?

jboss 4.2.3.GA 版本

jboss version 4.2.3.GA

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(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;
    }
}

当 jboss/hibernate 尝试创建表house"时，它抛出以下异常:

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

推荐答案

请尝试以下操作:

@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 {
    ...
}

请注意，这也应该允许您创建多列索引(基于索引名称):

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.:顺便说一句，您使用的是哪个版本的 Hibernate?什么数据库/方言?

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

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