@TableGenerator可以保存表中最后使用的ID而不是下一个可用的ID吗？ [英] Can @TableGenerator save the last used id in the table instead of the next available?

问题描述

我需要连接到供应商数据库并插入客户数据。用于生成新客户ID的序列表存储上次使用的ID（不是下一个可用的ID）。我无法在jpa或hibernate文档中找到任何可以指示hibernate将seq表中的id视为最后一次使用而不是下一个可用（使用@TableGenerator时）的方法。

是否需要编写一个自定义生成器，其行为与@TableGenerator基本相同，唯一的区别是序列表中值的处理方式是什么？

我的客户实体定义如下：

  @Entity 
 public class Customer {
 
 @Id 
 @TableGenerator（name =cust_gen，table =SEQUENCE，pkColumnName =target，
 pkColumnValue =customer，valueColumnName =id，allocationSize = 1）
 @GeneratedValue（strategy = GenerationType.TABLE，generator =pat_gen）
 public long getCustomer_id（）{
 return customer_id; 
} 
 
 public void setCustomer_id（Long id）{
 this.customer_id = id; 
} 
 
 ... 
 
} 
  

谢谢！

解决方案

我有同样的问题。以这种方式修复它：
使用Hibernate org.hibernate.annotations.GenericGenerator而不是像这样持久化TableGenerator：

  import javax.persistence.GeneratedValue; 
 import javax.persistence.GenerationType; 
 import org.hibernate.annotations.GenericGenerator; 
 
 @Entity 
 @Table（name =name）
 public class Name implements Serializable {
 
 private static final long serialVersionUID = 1L; 
 
 @Id 
 @GeneratedValue（strategy = GenerationType.TABLE，generator =names）
 @GenericGenerator（name =names，strategy =com.ourpackage.SybaseTableGenerator ，参数= {
 @Parameter（name =table_name，value =new_key_numbers），
 @Parameter（name =value_column_name，value =key_number），
 @参数（name =segment_column_name，value =name），
 @Parameter（name =segment_value，value =names_key）}）
 @Column（name =names_id）
私人长ID; 
  

并创建您自己的生成器（我使用名称com.ourpackage.SybaseTableGenerator）：

  import java.io.Serializable; 
 
 import org.hibernate.engine.spi.SessionImplementor; 
 import org.hibernate.id.enhanced.TableGenerator; 
 
 @SuppressWarnings（UnusedDeclaration）
公共类SybaseTableGenerator扩展TableGenerator {
 $ b $ @Override 
 public synchronized Serializable generate（SessionImplementor session，Object obj） {
 return（Long）super.generate（session，obj）+ 1; 
 
 
 
 
 
 
 $ b 
有点棘手， p> 
I need to connect to a vendor db and insert customer data.  The sequence table used to generate new customer ids stores the last used id (not the next available).  I couldn't find anything in the jpa or hibernate docs that would indicate a way to tell hibernate to treat the id in the seq table as last used instead of next available (when using @TableGenerator).

Do I need to write a custom generator that will behave essentially the same as @TableGenerator with the only difference being the way the value in the sequence table is treated?

My Customer entity is defined as follows:
@Entity
public class Customer {

    @Id
    @TableGenerator(name = "cust_gen", table = "SEQUENCE", pkColumnName = "target",
        pkColumnValue = "customer", valueColumnName = "id", allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.TABLE, generator = "pat_gen")
    public long getCustomer_id() {
          return customer_id;
    }

    public void setCustomer_id(Long id) {
    this.customer_id = id;
}

    ...

}
Thanks!
解决方案
I had the same problem. Fixed it this way:
Use Hibernate org.hibernate.annotations.GenericGenerator instead of persistance TableGenerator like this:
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import org.hibernate.annotations.GenericGenerator;

@Entity
@Table(name = "name")
public class Name implements Serializable {

private static final long serialVersionUID = 1L;

@Id
@GeneratedValue(strategy = GenerationType.TABLE, generator = "names")
@GenericGenerator(name = "names", strategy = "com.ourpackage.SybaseTableGenerator", parameters = {
        @Parameter(name = "table_name", value = "new_key_numbers"),
        @Parameter(name = "value_column_name", value = "key_number"),
        @Parameter(name = "segment_column_name", value = "name"),
        @Parameter(name = "segment_value", value = "names_key") })
@Column(name = "names_id")
private Long id;
And create your own generator (I used name com.ourpackage.SybaseTableGenerator):
import java.io.Serializable;

import org.hibernate.engine.spi.SessionImplementor;
import org.hibernate.id.enhanced.TableGenerator;

@SuppressWarnings("UnusedDeclaration")
public class SybaseTableGenerator extends TableGenerator {

    @Override
    public synchronized Serializable generate(SessionImplementor session, Object obj) {
        return (Long) super.generate(session, obj) + 1;
    }
}
A little bit tricky but it works ;)

                        
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