Spring 数据 JPA 使用本机查询加载惰性关联

Question

I am querying an entity by using a Postgres specific JSON operator (like @> ). To achieve that, the query needs to be decorated with @Query(nativeQuery = true) . My plan is to fetch the abovementioned entity along with some of its lazy associations. If I were using JPQL I'd simply JOIN FETCH the entity associations, but in this case I can't.

Please share some suggestions.. thanks

Answer 1

With plain Spring Data, you are out of luck because it is simply so limited. You have to use Hibernate APIs to achieve what you want with a native query. There you can specify for a query that you want to materialize some columns for the association of an entity eg

List<Entity1> list = session.createNativeQuery("select {t1.*}, {t2.*} from tbl1 t1 join tbl2 t2 ...", Entity1.class)
    .addEntity("t1", Entity1.class)
    .addJoin("t2", "t1", "associationName")
    .getResultList();

Alternatively, you can introduce a custom SQLFunction to model this PostgreSQL operator and still continue to use JPQL/HQL. See a similar answer for supporting array functions in PostgreSQL: HQL - Check if an Array contains a value