Hibernate 空字符串用于 PostgreSQL 8.3 和 Oracle 11g 的相等限制

发布于 2024-10-29 03:38:36 字数 883 浏览 2 评论 0原文

我遇到了如何检查 Oracle 11g 和 PostgreSQL 之间的空字符串的问题使用 Hibernate 限制

对于我的特定应用程序， PostgreSQL 使用 2 个单引号 '' 保存空值 while Oracle 将空值保存为 NULL

检查值是否为空的代码是

 public void AssureNotEmpty() { ...

     //For Oracle 11g    
     valueRestriction = Restrictions.isNotNull(propertyValueAlias);


     //For PostgreSQL
     valueRestriction = Restrictions.and(Restrictions.isNotNull(propertyValueAlias),
                        Restrictions.ne(propertyValueAlias, ""));

Restrictions.ne(propertyValueAlias, "") 当值不为空时在 Oracle 上失败，因为它将被解释为 value != NULL （这将始终为 false），因为 Hibernate 使 Oracle 将“”解释为 NULL。

那么如何使函数与数据库平台无关（因为现在我必须检测正在运行的是哪个数据库，PostgreSQL 还是 Oracle）？

或者我完全误解了什么？

原文

Extending on
How does hibernate use an empty string for an equality restriction?

I am having a problem about how to check for an empty string between Oracle 11g and PostgreSQL
using Hibernate Restriction

For my specific application,
PostgreSQL saves empty value using 2 single quotes ''
while Oracle saves empty value as NULL

The code to check whether the value is empty of not is

 public void AssureNotEmpty() { ...

     //For Oracle 11g    
     valueRestriction = Restrictions.isNotNull(propertyValueAlias);


     //For PostgreSQL
     valueRestriction = Restrictions.and(Restrictions.isNotNull(propertyValueAlias),
                        Restrictions.ne(propertyValueAlias, ""));

Restrictions.ne(propertyValueAlias, "") fails on Oracle when the value is NOT empty because it will be interpreted as value != NULL (which will ALWAYS be false) as Hibernate makes Oracle interprets "" as NULL.

So how can I make the function Database-platform agnostic (because now I have to detect which database is running, PostgreSQL or Oracle)?

Or am I completely misunderstanding something?

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