（懒）LEFT OUTER JOIN使用Hibernate Criteria API [英] (Lazy) LEFT OUTER JOIN using the Hibernate Criteria API

问题描述

我想使用Criteria API在两个表之间执行LEFT OUTER JOIN。我在Hibernate文档中找到的所有方法都是这种方法：

$ p $ Criteria criteria = this.crudService
.initializeCriteria（Applicant .class）
.setFetchMode（products，FetchMode.JOIN）
.createAlias（products，product）;


然而，这要么执行一个内连接，要么执行一个右外连接，因为它的结果数量很多返回。

我也想让我的连接变得懒惰。我该怎么做？

干杯！

更新：使用别名会自动连接INNER JOIN。在我还没有掌握的背景故事中有一些东西。所以，今天没有别名。这给我留下了对两个表应用限制的问题，因为它们都有一个列（或属性，如果这更合适的话）' name '。

<如果您需要在产品表上留下加入，请执行以下操作：

..... createAlias（products，
product，Criteria.LEFT_JOIN）;

I want to perform a LEFT OUTER JOIN between two tables using the Criteria API. All I could find in the Hibernate documentation is this method:

Criteria criteria = this.crudService
            .initializeCriteria(Applicant.class)
            .setFetchMode("products", FetchMode.JOIN)
            .createAlias("products", "product");

However, this either performs an inner join or a right outer join, because of the number of results it returns.

I also want my join to be Lazy. How can I do this?

Cheers!

UPDATE: It seems that using aliases makes the join INNER JOIN automatically. There is something in the "background story" I have not grasped yet. So, no alias today. This leaves me with the problem of applying restrictions to the two tables, because they both have a column (or property, if this is more appropriate) 'name'.

解决方案

If you need to left join on the products table just do:

.....createAlias("products", "product", Criteria.LEFT_JOIN);

这篇关于（懒）LEFT OUTER JOIN使用Hibernate Criteria API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！