Hibernate的@OneToMany - 映射到多个连接表 [英] Hibernate @OneToMany - mapping to multiple join tables

问题描述

考虑下面的域模型：

Issue
- id
- List<Comment>

Entry
- id
- List<Comment>

Comment
-id
-comment

在我的设计，我试图创建两个连接表管理协会; issue_comments和entry_comments。我以为@OneToMany的问题和放大器;入境，但你如何映射多个连接表？使用Hibernate注释，这可怎么映射？

In my design, I was attempting to create two join tables to manage the associations; issue_comments, and entry_comments. I assumed @OneToMany on Issue & Entry, but how do you map the multiple join tables? Using hibernate annotations, how can this be mapped?

推荐答案

如果你可以改变你的域模型，看看通过的克莱图斯。你只有一个表进行更新，因此将提供更好的性能。

If you can change your domain model, take a look at answer given by cletus. You'll only have one table to update so it'll provide better performance.

如果你不能改变你的域模型，你可以映射你的注释通过连接表的集合：

If you cannot change your domain model, you can map your comment collections via join tables:

// ENTRY
@OneToMany
@JoinTable(
        name="ENTRY_COMMENTS",
        joinColumns = @JoinColumn( name="entry_id"),
        inverseJoinColumns = @JoinColumn( name="comment_id")
)
public List<Comment> getComments()

// ISSUE
@OneToMany
@JoinTable(
        name="ISSUE_COMMENTS",
        joinColumns = @JoinColumn( name="issue_id"),
        inverseJoinColumns = @JoinColumn( name="comment_id")
)
public List<Comment> getComments()

您的意见仍然会在这两个问题和条目相同的表;只联接表会有所不同。注意，这是一个单向关系。详情<一个href=\"http://docs.jboss.org/hibernate/stable/annotations/reference/en/html/entity.html#entity-mapping-association-collections\"相对=nofollow>这里

Your comments would still be in the same table for both issues and entries; only join tables will be different. Note that this is a uni-directional relationship. Details are here

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