JPA / Hibernate有条件的onetomany关系？ [英] JPA/Hibernate conditionally onetomany relationship?

问题描述

我使用Hibernate Tools直接从数据库生成DAO和类。在数据库中有两个表（表A和B），并且从A到B之间存在一对多关系（B中的多行映射到单个A）。

<在生成的A（A类）代码中，有一个B类集合，它反映了一对多关系。但是，我不需要属于A的所有B行都在结果中（比如，我只需要B行中列x为NULL的行）。我不明白这是如何实现的。任何想法？

非常感谢！

解决方案

@Where 注释

I am using Hibernate Tools to generate the DAO and classes straight from database. There are two tables (table A and B) in the database, and there is a one to many relationship from A to B (multiple rows in B mapped to single A).

In the generated code of A (class A), there is a collection of class B, which reflects the one to many relationship. However, I don't need all the rows of B that belong to A to be in the result (say, I only want rows from B where column x is NULL). I don't see how this can be achieved. Any idea?

Thanks a lot!

解决方案

You can use the @Where annotation

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