如何将两列作为hibernate注记类中的主键 [英] how to make two column as a primary key in hibernate annotation class

问题描述

这是我的注释类，我希望 userId 和 groupId 列作为主键。
我发现了更多问题（问题），但没有找到相关答案。
我声望较低，所以我无法评论帖子，所以我在这里提出我的问题。

这是我的代码.. p>

  import javax.persistence.Column; 
 import javax.persistence.EmbeddedId; 
 import javax.persistence.Entity; 
 import javax.persistence.GeneratedValue; 
 import javax.persistence.GenerationType; 
 import javax.persistence.Id; 
 import javax.persistence.Table; 
 
 import org.hibernate.annotations.NaturalId; 
 
 @Entity 
 @Table（name =user_group）
 public class user_group {
 
 @Column（name =serviceProvider）
 private String serviceProvider; 
 
 @Column（name =enterpriseId）
 private String enterpriseId; 
 
 @Column（name =department）
 private String department; 
 
 @Column（name =trunkGroupName）
 private String trunkGroupName; 
 @Id 
 @Column（name =userId）
 private String userId; 
 
 
 @Column（name =groupId）
私有字符串组; 
 
 
 public String getUserId（）{
 return userId; 
} 
 
 
 public void setUserId（String userId）{
 this.userId = userId; 
} 
 
 
 public String getGroup（）{
 return group; 
} 
 
 
 public void setGroup（String group）{
 this.group = group; 
} 
 
 public String getServiceProvider（）{
 return serviceProvider; 
} 
 
 public void setServiceProvider（String serviceProvider）{
 this.serviceProvider = serviceProvider; 
} 
 
 public String getEnterpriseId（）{
 return enterpriseId; 
} 
 
 public void setEnterpriseId（String enterpriseId）{
 this.enterpriseId = enterpriseId; 
} 
 
 public String getDepartment（）{
 return department; 
} 
 
 public void setDepartment（String department）{
 this.department = department; 
} 
 
 public String getTrunkGroupName（）{
 return trunkGroupName; 
} 
 
 public void setTrunkGroupName（String trunkGroupName）{
 this.trunkGroupName = trunkGroupName; 
} 
 
 
} 
  

解决方案

您应该创建一个新的 @Embeddable 类，其中包含PK字段：

  @Embeddable 
 public class user_groupId implements Serializable {
 @Column（name =userId）
 private String userId; 
 
 @Column（name =groupId）
 private String group; 
} 
  

并将它用于 @Entity 作为 @EmbeddedId ：

  @Entity 
 public class user_group {
 
 @EmbeddedId 
 user_groupId id; 
 
 ... 
} 
  

您也可以使用 @IdClass 注解。

Pascal Thivent的出色的答案详细阐述了细节。您还可以查看这个其他答案，前一段时间我发布了一个几乎相同的问题。

请注意，如果您已经控制了数据库结构，那么您也可以考虑避免组合键。 这样做有一些原因。

This is my annotation class and i want userId and groupId column both as primary key. I have found more questions (Question) about this, but didn't found relevant answer. I have less reputation, so I am not able to comment on posts, So I am putting my question here.

This is my code..

import javax.persistence.Column;
import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

import org.hibernate.annotations.NaturalId;

@Entity
@Table(name="user_group")
public class user_group {

@Column(name="serviceProvider")
private String serviceProvider;

@Column(name="enterpriseId")
private String enterpriseId;

@Column(name="department")
private String department;

@Column(name="trunkGroupName")
private String trunkGroupName;
@Id
@Column(name="userId")
private String userId;


@Column(name="groupId")
private String group;


public String getUserId() {
    return userId;
}


public void setUserId(String userId) {
    this.userId = userId;
}


public String getGroup() {
    return group;
}


public void setGroup(String group) {
    this.group = group;
}

public String getServiceProvider() {
    return serviceProvider;
}

public void setServiceProvider(String serviceProvider) {
    this.serviceProvider = serviceProvider;
}

public String getEnterpriseId() {
    return enterpriseId;
}

public void setEnterpriseId(String enterpriseId) {
    this.enterpriseId = enterpriseId;
}

public String getDepartment() {
    return department;
}

public void setDepartment(String department) {
    this.department = department;
}

public String getTrunkGroupName() {
    return trunkGroupName;
}

public void setTrunkGroupName(String trunkGroupName) {
    this.trunkGroupName = trunkGroupName;
}


}

解决方案

You should create a new @Embeddable class containing the PK fields:

@Embeddable
public class user_groupId implements Serializable { 
    @Column(name="userId")
    private String userId;

    @Column(name="groupId")
    private String group;
}

And use it in the @Entity as an @EmbeddedId:

@Entity
public class user_group {

    @EmbeddedId
    user_groupId id;

    ...
}

You could also use the @IdClass annotation to that effect.

This excellent answer by Pascal Thivent elaborates on the details. You can also take a look at this other answer I posted to a almost identical question some time ago.

As a side note, if you've got control over the DB structure, you might also consider avoiding composite keys. There are some reasons to do so.

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