JPA引用表映射 [英] JPA reference table mapping

问题描述

有两个主要的 @Entity 类反映了这些表：

There are two main @Entity classes reflecting these tables:

TableA {id,name}
TableB {id,name}

和一个参考表

TableC {tableA.id,tableB.id}

问题是：如何使用 @OneToMany TableA 的实体字段c $ c>对TableB对象列表的反映：

Question is: how to map a TableA's entity's field with @OneToMany realation to TableB objects list:

@OneToMany
??????????
private List<TableBEntity> tableBItems;

推荐答案

如果您真正拥有的是OneToMany（这意味着在 TableC 中，给出 tableB.id 最多出现一次，然后映射如下：

If what you really have is a OneToMany (which means that a give tableB.id appears at most once in TableC), then the mapping is the following:

@OneToMany
@JoinTable(name = "TableC",
           joinColumns = @JoinColumn(name = "TABLE_A_ID"),
           inverseJoinColumns = @JoinColumn(name = "TABLE_B_ID"))
private List<TableBEntity> tableBItems;

否则，你所拥有的实际上是ManyToMany，并且映射是相同的，除了 @OneToMany 必须由 @ManyToMany 替换。

Else, what you have is in fact a ManyToMany, and the mapping is the same, except that @OneToMany must be replaced by @ManyToMany.

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