I've run into some code which behaviour is not clear for me.
We have first entity:
@Data
@Entity
@Table(name = "Info")
public class Info {
@OneToOne
@JoinColumn(name = "data_id")
private Data data;
}
and second one:
@Data
@Entity
@Table(name = "Data")
public class Data {
@Id
private Long dataId
}
And we have next method for retrieving data:
@Query(value = "SELECT * FROM Info i inner join Data d on d.data_id=i.data_id",
nativeQuery = true)
List<Info> getInfo() {}
As nativeQuery = true is present I expect this method make just one SQL select and retrieve me data. But If I take a look at logs actually there are 2 selects:
SELECT * FROM Info i inner join Data d on d.data_id=i.data_id;
SELECT * FROM Data d where d.data_id = 123;
Why this is happening ? How to fix it to make only one select and retrieve all data ?
CodePudding user response:
It's not possible to specify native query fetches without Hibernate specific APIs. I would suggest you to use a normal JPQL/HQL query:
@Query(value = "FROM Info i join fetch i.data")
List<Info> getInfo();
This will do the same as your native query but at the same time just run only a single query.
CodePudding user response:
Your Data
entity column is not match with query you put in query is d.data_id
but actual column name is dataId
and nativeQuery = true
is for Relational query
not JPQL query
@Query(value = "SELECT * FROM Info i INNER JOIN Data d ON d.dataId = i.data_id",
nativeQuery = true)
List<Info> getInfo() {}