I have used Hibernate to map Java objects to PostgreSQL database. UserDetails class is the entity class used to add user.It contains an embedded object called Address.
UserDetails.java
@Entity
@Table(name="USER_DETAILS")
public class UserDetails {
@Id @GeneratedValue(strategy=GenerationType.AUTO)
@Column(name="USER_ID")
private int userId;
@Column(name="USER_NAME")
private String userName;
@Temporal(TemporalType.DATE)
@Column(name="JOINED_DATE")
private Date joinedDate;
@Column(name="DESCRIPTION")
private String description;
@Embedded
private Address address;
}
Address object contains detail about address like city,pincode,street and state.
Address.java
import javax.persistence.Embeddable;
@Embeddable
public class Address {
private String street;
private String city;
private String state;
private String pincode;
}
The class containing main method is below:
public class HibernateTest {
public static void main(String[] args){
UserDetails user = new UserDetails();
UserDetails user1 = new UserDetails();
user.setUserName("First User");
Address newAddress = new Address();
newAddress.setCity("Pune");
newAddress.setPincode("411057");
newAddress.setState("Maharashtra");
newAddress.setStreet("Hinjewadi");
user.setAddress(newAddress);
user.setDescription("just like that");
user.setJoinedDate(new Date());
user1.setUserName("Second User");
user1.setDescription("great here");
user1.setJoinedDate(new Date());
SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
Session session = sessionFactory.openSession();
session.beginTransaction();
session.save(user);
session.save(user1);
session.getTransaction().commit();
session.close();
user = null;
session = sessionFactory.openSession();
session.beginTransaction();
user = session.get(UserDetails.class, 1);
System.out.println(user.getUserName());
session.close();
sessionFactory.close();
}
}
The generated SQL query is as below, which shows that columns are not added in the same order in which they were declared.
Hibernate: create sequence hibernate_sequence start 1 increment 1
Hibernate: create table USER_DETAILS (USER_ID int4 not null, city varchar(255), pincode varchar(255), state varchar(255), street varchar(255), DESCRIPTION varchar(255), JOINED_DATE date, USER_NAME varchar(255), primary key (USER_ID))
Is there any rule in which columns are added in hibernate?
