用于数据库视图的JPA/SpringBoot存储库(非表) [英] JPA/SpringBoot Repository for database view (not table)

问题描述

我正在尝试为视图创建JPA实体.在数据库层中，表和视图应该相同.

I'm attempting to create a JPA entity for a view. From the database layer, a table and a view should be the same.

但是，问题开始出现并且有两个方面:

However, problems begin to arise and they are two fold:

1. 尝试设置正确的注释时.视图没有与之关联的主键，但是如果没有在字段上注释正确的@javax.persistence.Id，则在运行时会抛出org.hibernate.AnnotationException: No identifier specified for entity.

1. When attempting to setup the correct annotations. A view does not have a primary key associated with it, yet without the proper @javax.persistence.Id annotated upon a field, you will get an org.hibernate.AnnotationException: No identifier specified for entity thrown at Runtime.

Spring Boot JpaRepository接口定义要求ID类型扩展Serializable，这排除了使用java.lang.Void作为解决方案的一种变通方法，因为该方法在视图实体上缺少id. p>

The Spring Boot JpaRepository interface definition requires that the ID type extends Serializable, which precludes utilizing java.lang.Void as a work-around for the lack of an id on an view entity.

与缺乏主键的视图进行交互的正确JPA/SpringBoot/Hibernate方法是什么?

What is the proper JPA/SpringBoot/Hibernate way to interact with a view that lacks a primary key?

推荐答案

我也正在探讨该主题.我最终使用了Spring Data JPA 界面-原生查询的基于Projections的投影.

I was exploring that topic too. I ended up using Spring Data JPA Interface-based Projections with native queries.

我创建了一个接口，确保大写部分与数据库列名称匹配:

I created an interface, making sure the UPPERCASE part matches the DB Column names:

public interface R11Dto {

   String getTITLE();

   Integer getAMOUNT();

   LocalDate getDATE_CREATED();
}

然后，我为一个与视图没有任何关系的实体(用户)创建了一个存储库.在该存储库中，我创建了一个简单的本地查询. vReport1_1是我的观点.

Then i created a repository, for an Entity (User) not related in any way to the view. In that repository i created a simple native query. vReport1_1 is my view.

public interface RaportRepository extends JpaRepository<User, Long> {

   @Query(nativeQuery = true, value = "SELECT * FROM vReport1_1 ORDER BY DATE_CREATED, AMOUNT")
   List<R11Dto> getR11();

}

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