如何在Hibernate中使用@Where [英] How to use @Where in Hibernate

问题描述

搜索了几个小时，但是我仍然陷入了用JPA的PlayFramework学习曲线。我正在建立一个可以发布帖子的示例网站。但是这些帖子可能会有这样的状态：

• PostDraft（发布是草稿，不发布）


• PostPublished（可发布帖子）

这些状态存储在一个单独的表中。显然，草稿帖子不应该是可见的。

所以我有这些类：

• 页面类（从表中获取页面信息，1页可以有多个帖子）
  
• 帖子类（帖子可以在草稿和发布）

在我的页面类中，我有：

  @Column（name =POSTS_REF）
 @Where（clause =PostPublished）
 private List< Posts> userPosts; 
  

但这不起作用！那么，如何指定一个where子句，只加载处于已发布状态的帖子而不使用JPQL ??

谢谢！

更新：2011-10-11

表格：帖子 with columns：
- id
- title
- state_ref（引用状态表的ID）
- content

Table： em> States with columns：
- id
- statename

所以我想说一句：

  select * 
 from post内部联接状态on posts.state_ref = states.id 
 where states.statename ='PostPublished' 
  

UPDATE 2011-10-13 $ b

这是我目前的修改，在我的页面类中：但它也不起作用。

  / **链接到状态* / 
 @JoinColumn（name =STATES_REF）
 @OneToOne 
 @Where（clause =states.statename ='PostPublished'）
公共MyState状态; 
  

UPDATE 2012-02-13
Emt的答案适用于我试过类似：

 >  @Column（name =POSTS_REF）
 @Where（clause =state ='PostPublished'）
 private List< Posts> userPosts; 
  

或

  @Column（name =POSTS_REF）
 @Where（clause =PostPublished = true）
 private List< Posts> userPosts; 
  

取决于发布实体。

Searched for a few hours, but I'm stuck in a my learning curve for PlayFramework with JPA. I'm building a sample website where posts can be made. But these posts can have the states:

• PostDraft (post is a draft, do not publish)
• PostPublished (post can be published)

These states are stored in a seperate table. Obviously, the draft state posts should not be visible yet.

So I have these classes:

• Page class (getting the page information from table, 1 page can have multiple posts)
• Posts class (posts can be in draft and published)

In my page class I have:

@Column(name="POSTS_REF")
@Where(clause="PostPublished")
private List<Posts> userPosts;

But this is not working! So, how can I specifify a where clause, to load only the posts that are in published state without using JPQL??

Thanks!

UPDATE: 2011-10-11

Table: Posts with columns: - id - title - state_ref (reference to the ID of States table) - content

Table: States with columns: - id - statename

So I want to say something like:

select * 
from posts inner join states on posts.state_ref = states.id
where states.statename = 'PostPublished'

UPDATE 2011-10-13

This is my current modification, in my page class: but it does not work either.

/** link to the states */
@JoinColumn(name = "STATES_REF")
@OneToOne
@Where(clause = "states.statename = 'PostPublished'")
public MyState state;

UPDATE 2012-02-13 Emt's answer worked for me after all.

解决方案

Try something like:

@Column(name="POSTS_REF")
@Where(clause="state='PostPublished'")
private List<Posts> userPosts;

or

@Column(name="POSTS_REF")
@Where(clause="PostPublished=true")
private List<Posts> userPosts;

depending on the status field type on your Post entity.

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