如何使用现有的Oracle序列在hibernate中生成id？ [英] How to use existing Oracle sequence to generate id in hibernate?

问题描述

我有一个名为 PRODUCT_ID_SEQ 的遗留Oracle数据库。

以下是我需要生成正确ID的 Product 类的映射：

  public class Product {
 @GeneratedValue（strategy = GenerationType.SEQUENCE，
 generator =retailerRaw_seq）
 @SequenceGenerator （name =retailerRaw_seq，
 sequenceName =PRODUCT_ID_SEQ）
 private Long ID; 
 
 ... 
} 
  

但看起来像ids生成间隔为50，如1000,1050,1100等。这对应于默认值 allocationSize property = 50.这意味着Hibernate并没有实际使用已经在db中定义的序列。

我如何让Hibernate使用这个序列？ 回答原始问题：

  @SequenceGenerator（name =EL_SEQ，sequenceName =EL_SEQ，allocationSize = 1）
  

设置值为增量的 allocationSize 通过。

I have legacy Oracle db with a sequence named PRODUCT_ID_SEQ.

Here is the mapping of Product class for which I need generate correct ids:

public class Product {
   @GeneratedValue(strategy = GenerationType.SEQUENCE, 
                       generator = "retailerRaw_seq")
   @SequenceGenerator(name = "retailerRaw_seq", 
                      sequenceName = "PRODUCT_ID_SEQ")
   private Long id;

   ...
}

But looks like ids are generated with an interval of 50, like 1000, 1050, 1100 etc. This corresponds to the default value of allocationSize property = 50. So that means that Hibernate doesn't actually use the sequence which is already defined in the db.

How do I make Hibernate use the sequence?

解决方案

The answer to the original question:

@SequenceGenerator(name="EL_SEQ", sequenceName="EL_SEQ",allocationSize=1)

It is allocationSize that sets the value to increment by.

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