Hibernate Native SQL

43.2K views

Hibernate Native SQL - Introduction Use parameter binding in native SQL queries Adding scalars Native Joins Adding joins with entity mapping Basic Result set mapping using @SqlResultSetMapping Mapping Non-managed entities via result transformer Mapping Non-managed entities via result Custom Transformer

Previous: Native Joins Next: Basic Result set mapping using @SqlResultSetMapping

Adding joins with entity mapping.

We can also use addEntity() and addJoin() methods to fetch the data from associated table using tables join. The above query can be re-written as following;

A quick sample. Check out the JAVA class and SQL file

// {
package com.tu.nativesqlsample;
import java.util.List;
import java.util.logging.Logger;
import org.hibernate.Session;
import com.tu.hibernate.HibernateUtil;
import com.tu.hibernate.entity.Team;
import com.tu.hibernate.entity.User;
public class NativeQueryNativeJoinWithEntity {
    static Logger logger = Logger.getLogger(NativeQueryNativeJoinWithEntity.class.getName());
    static String dash = "--------------------------------------------------------------";
    public static void main(String[] args) {
        Session session = null;
        try {
            session = HibernateUtil.getSessionFactory().openSession();
            // Mapping Native JOIN query to Entities
            nativeJoinWithEntity(session);
        } catch (Exception e) {
            logger.warning(e.toString());
        } finally {
            if (session != null) {
                session.close();
            }
        }
        HibernateUtil.shutdown();
    }
    @SuppressWarnings("unchecked")
    public static void nativeJoinWithEntity(Session session) {
        logger.info(dash);
      // }
        List<Object[]> usersJoin = session
                .createNativeQuery(
                        "select u.*, t.* from user u left outer join team t on u.team_id=t.team_id  where u.user_id=?")
                .addEntity("u", User.class).addJoin("t", "u.team").setParameter(1, 1).list();
        usersJoin.stream().forEach(object -> { // The user's object list would contain a User instance and a
                                                // "joined"
                                                // team instance.
            User userJoin = (User) object[0];
            logger.info("User - " + userJoin.getName());
            logger.info("User Domain - " + userJoin.getDomain().getDomainName());

Notice the second query, which fetches the Domain details. This is the eager Loading of the requested object
[aliasname].* is used to return all properties of an entity. When we use addEntity() and addJoin() with join queries like above it returns both the objects, as shown above.