为什么Hibernate切换到CLOB使用LONG？ [英] Why has Hibernate switched to use LONG over CLOB?

问题描述

看起来Hibernate在版本3.5.5（我们从3.2.7升级）开始使用 LONG 数据类型而不是 CLOB code>为code> type =text。

这会导致问题，因为<$ Oracle中的c $ c> LONG 数据类型是旧的过时数据类型（请参见 http://www.orafaq.com/wiki/LONG ）不应该被使用，并且表格不能有多于一列，其中 LONG 作为数据类型。

有人知道为什么这个已经改变了吗？

我试图设置Oracle SetBigStringTryClob 属性为true（如 Hibernate> CLOB > Oracle :( ），但这并不影响数据类型映射，但只影响与我的案例无关的数据传输内部消息。

一种可能的修复因为这是重写 org.hibernate.dialect.Oracle9iDialect ：

  public class Oracle9iDialectFix扩展了Oracle9iDialect {
 public Oracle9iDialectFix（）{
 super（）; 
 registerColumnType（Types.LONGVARCHAR，clob）; 
 registerColumnType（Types.LONGNVARCHAR，clob）; 
} 
} 
  

然而这是最后的手段 - 覆盖这个类是更接近分叉Hibernate，我宁愿避免这样做。

任何人都可以解释为什么这样做了吗？
这是否应该作为bug提出？

[UPDATE]：我创建了 http://opensource.atlassian.com/projects/hibernate/browse/HHH-5569 ，让我们看看会发生什么。

解决方案

看起来这个问题的解决方案是使用 materialized_clob ，至少这就是由Gail Badner在 HHH-5569 上说。

这完全没有帮助我（我留下了相关评论），但可能对此处的其他人有所帮助。无论如何，该错误被拒绝，我可以做的事情很少，但使用重叠方言：（$ / b $ b

It looks like that Hibernate started using LONG data type in version 3.5.5 (we upgraded from 3.2.7) instead of CLOB for the property of type="text".

This is causing problems as LONG data type in Oracle is an old outdated data type (see http://www.orafaq.com/wiki/LONG) that shouldn’t be used, and tables can’t have more than one column having LONG as a data type.

Does anyone know why this has been changed?

I have tried to set the Oracle SetBigStringTryClob property to true (as suggested in Hibernate > CLOB > Oracle :(), but that does not affect the data type mapping but only data transfer internals which are irrelevant to my case.

One possible fix for this is to override the org.hibernate.dialect.Oracle9iDialect:

public class Oracle9iDialectFix extends Oracle9iDialect {
  public Oracle9iDialectFix() {
    super();
    registerColumnType(Types.LONGVARCHAR, "clob");
    registerColumnType(Types.LONGNVARCHAR, "clob");
  }
}

However this is the last resort - overriding this class is step closer to forking Hibernate which I would rather avoid doing.

Can anybody explain why this was done? Should this be raised as a bug?

[UPDATE]: I have created http://opensource.atlassian.com/projects/hibernate/browse/HHH-5569, let's see what happens.

解决方案

It looks like the resolution to this issue is to use materialized_clob, at least that's what's being said by Gail Badner on HHH-5569.

This doesn't help me at all (and I left relevant comment about that) but might be helpful for someone else here. Anyway the bug is rejected and there is very little I can do about it but use overriden dialect :(

这篇关于为什么Hibernate切换到CLOB使用LONG？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！