外键是组合主键的一部分时Hibernate实体映射？ [英] Hibernate Entity mapping when Foreign key is part of the composite primary key?

问题描述

我有一个带有复合PK的表：Customer
我有一个没有PK的View：购买

绑定我的实体，Hibernate迫使我声明一个PK。
所以我创建了一个复合PK For Purchase。

购买：

  @Entity 
 @Table（name =PURCHASE）
公共类购买{
 
 @EmbeddedId 
私人PurchasePK ID; 
} 
  

PuchasePK：

 
 
 
 
 
 
 
 $ b $ private $ String custLastname; 
 
 @Column（name =OBJ_NAME）
 private long objectName; 
} 
  

客户很简单：

  @Entity 
 @Table（name =CUSTOMER）
 public class Customer {
 
 @EmbeddedId 
私人CustomerPK ID; 
 
 $ / code> 

借助其复合PK：



  @Embeddable 
 public class CustomerPK {
 
 @Column（name =CUST_LASTNAME）
 private String custLastname; 
 
 @Column（name =CUST_NAME）
私人长期custName; 
} 
  

现在我想通过匹配表CUST_NAME来在Customer中创建一个OneToMany属性。

  @OneToMany 
私人列表< Purchase> listPurchases; 
  

我该如何做？



我搜索了很多，它总是归结为不能在1列上做FK，如果PK有2列的话......

PS：I' m使用JPA 1，所以我无法访问@MapsId。

PS2：我的真实模型与客户&购买以及用于PKs的属性不是varchar而是Long。 解决方案

直接回答您的问题 - 我认为您无法做到那。
我建议通过引入CUSTOMER_ID字段来重新考虑这个模型，因为第一个+姓氏在实践中并不是独一无二的。此外，由于可能存在Mike Smith，John Smith作为客户，因此仅以姓氏加入会给您带来混购。具有数字ID将解决我所想的所有问题。

I have a Table with a composite PK : Customer I have a View with no PK : Purchase

To bind my Entity, Hibernate forces me to declare a PK. So I've created a composite PK For Purchase.

Puchase:

@Entity
@Table(name = "PURCHASE")
public class Purchase {

    @EmbeddedId
    private PurchasePK id;
}

PuchasePK:

@Embeddable
public class PurchasePK {

    @Column(name = "CUST_LASTNAME")
    private String custLastname;

    @Column(name = "OBJ_NAME")
    private Long objectName;
}

Customer is straight forward :

@Entity
@Table(name = "CUSTOMER")
public class Customer {

    @EmbeddedId
    private CustomerPK id;
}

With its composite PK:

@Embeddable
public class CustomerPK {

    @Column(name = "CUST_LASTNAME")
    private String custLastname;

    @Column(name = "CUST_NAME")
    private Long custName;
}

Now I want to create a OneToMany attribut in Customer by matching both table CUST_NAME.

@OneToMany
private List<Purchase> listPurchases;

How can i do that?

I've searched quite a bit and it always comes down to not being able to do FK on 1 column if the PK has 2 columns ...

PS: I'm using JPA 1, so I don't have access to @MapsId.

PS2: My real model is not about Customer & purchase and the attributs used for the PKs are not varchar but Long.

解决方案

Answering directly to your question - I think you cannot do that. I would suggest to rethink this model by introducing CUSTOMER_ID field since first+last name quite often are not unique from practice. Moreover joining only by last name will give you mix of purchases since there could be "Mike Smith", "John Smith" as a customers. Having numeric ID will solve all your problems I suppose.

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