使用 JPA 时 HQL 的异常行为（* 向读者提供的信息多于问题 * ）

发布于 2024-09-12 09:38:35 字数 689 浏览 2 评论 0原文

我试图在基于 JPA 的应用程序中出于某些报告目的而触发 hql 。我尝试的以下查询在启动时不断出现问题（因为我将其作为 NamedQuery 给出，所以在启动时检查了语法）。

不正确的查询：

SELECT t FROM Table_1 tb1 
INNER JOIN 
Table_2 tb2
where tb1.name = 'someName';

经过大量的排列和组合（并深入研究了查询的其他部分，这是我之前怀疑的），我意识到问题出在“t” 。 正确的查询应该是而不是上面的查询...

SELECT tb1 FROM Table_1 tb1
INNER JOIN 
Table_2 tb2
where tb1.name = 'someName';

请注意，HQL 期望 tb1 与表短名“tb1”相同>”

tableName 缩写和选择不匹配只会导致我面临的问题。令人惊讶的是，hibernate/JPA 并没有在堆栈中给出错误，但部署继续运行，我最终需要终止 java 进程才能退出它。

希望这对某人有帮助。

如果有人也能解释这种行为，那就太好了。

谢谢！！

原文

I was trying to fire hql for some reporting purpose in my JPA based application.
The following query that I tried kept conking out on startup (Since I had given it as a NamedQuery, it was checked for syntax at startup).

Incorrect Query:

SELECT t FROM Table_1 tb1 
INNER JOIN 
Table_2 tb2
where tb1.name = 'someName';

After lot of permutations and combinations (and digging through the other parts of the query, which I suspected earlier), I realized the problem lied in the "t". Instead of the query above, the correct query should have been...

SELECT tb1 FROM Table_1 tb1
INNER JOIN 
Table_2 tb2
where tb1.name = 'someName';

Notice that HQL expects the tb1 to be same as the Table shortname "tb1"

The tableName shortform and the select mismatch only resulted in the issue that I was facing. Surprisingly, hibernate/JPA does not give an error in the stack, but the deployment keeps on running through and I need to ultimately kill the java process to get out of it.

Hope this helps someone.

It would great, if somebody could also reason this behaviour.

Thanks!!

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哭了丶谁疼 2024-09-19 09:38:36

处理此类语句的最佳方法是将“变量”放在 SELECT 子句中与表别名相同的实践中。
那不是

"SELECT t from Table_1 T1"

发表像

"SELECT T1 from Table_1 T1"

“希望”这样对未来有帮助的声明。

The best way to deal with such statements it make it a PRACTICE to put the "Variable" in the SELECT clause same as the table Alias.
That is instead of