Create spring repository without entity

Question

I want to use spring data repository interface to execute native queries - I think this way is the simplest because of low complexity.

But when extending interface ex. CrudRepository<T, ID> I need to write T - my entity, which is not available.

My native queries does not return any concrete entity, so what is the best way to create spring repository without entity?

Answer 1

CrudRepository or JpaRepository were not designed to work without an <Entity,ID> pair.

You are better off creating a custom repo, inject EntityManager and query from there:

  @Repository   public class CustomNativeRepositoryImpl implements CustomNativeRepository {      @Autowired     private EntityManager entityManager;      @Override     public Object runNativeQuery() {         entityManager.createNativeQuery("myNativeQuery")          .getSingleResult();     } } 

Answer 2

Currently there is no functionality in JPA to create repositories with only native or JPQL/HQL queries (using @Query notation). To get around this, you can create a dummy object to insert into the extension interface like below:

@Entity public class RootEntity {     @Id     private Integer id; }  @Repository public interface Repository extends JpaRepository<RootEntity, Integer> { }