映射仅包含复合PK而没有@IdClass或@EmbeddedId的类 [英] Mapping a class that consists only of a composite PK without @IdClass or @EmbeddedId

问题描述

我有两个带有简单PK的表A和B.

I've got two tables A and B with simple PK's.

@Entity
public class A { 
    @Id
    public int idA;
}

@Entity
public class B { 
    @Id
    public int idB;
}

我想映射一个新的关联类AB，它简单地存储了A和B之间的关系，并带有复合PK idA + idB. AB没有任何额外的列，只有idA和idB之间的关系.

I want to map a new association class AB that simply stores the relations between A and B, with composite PK idA+idB. AB doesn't have any extra columns, just the relation between idA and idB.

是否可以使用单个类映射AB?我想避免创建新的ABId类，而只是将其用作AB中的@IdClass或@EmbeddedId，并且我不想将其与A上的@ManyToMany关联映射B.

Is it possible to map AB using a single class? I want to avoid having to create a new ABId class just to use it as @IdClass or @EmbeddedId in AB, and I don't want to map this with a @ManyToMany association on A or B.

推荐答案

为什么要映射这样的联接表?只需使用A和B之间的ManyToMany关联.当您向A中包含的B列表中添加B或从中删除B时，该连接表将被自动处理.

Why do you want to map such a join table? Just use a ManyToMany association between A and B. This join table will then be handled automatically when you'll add/remove a B to/from the list of Bs contained in A.

请参见 http://docs.jboss. org/hibernate/core/3.6/reference/zh-CN/html_single/#d0e11402

如果您确实想这样做，则只需将两个ID映射为@Id即可.主要类将是实体类本身(必须可序列化)，如

If you really want to do that, then just map the two IDs with the @Id notation. The primary class will be the entity class itself (which must be serializable), as explained in the hibernate reference documentation. Note that this is Hibernate-specific.

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