[FIXED] JPA/SpringBoot Repository for database view (not table)

Issue

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

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

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.

2. 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.

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

Solution

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

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

public interface R11Dto {

   String getTITLE();

   Integer getAMOUNT();

   LocalDate getDATE_CREATED();
}

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();

}

Answered By - Robert Niestroj
Answer Checked By - Marie Seifert (JavaFixing Admin)