In this method, we will create a relationship in such a way that both tables contain the same primary key value for the related record. So, we can say that here we used unidirectional as well as bidirectional relationships, because we can get either record through another record using its primary key. For example, if Person is inserted with id 1, you should get the PassportDetail record inserted with id 1 as well.
Here, we will create Person and PassportDetail classes to work this demo.
Use the following script to create the tables if you are not using hbm2dll=create|update:
Use the following script to create the passport_detail table:
CREATE TABLE `passport_detail` ( `id` bigint(20) NOT NULL AUTO_INCREMENT, `passportno` varchar(255) DEFAULT NULL, PRIMARY KEY (`id`) );
Use the following script to create the person table:
CREATE TABLE `person` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `FK_PASSPORT_DETAIL_ID` (`id`),
CONSTRAINT `FK_PASSPORT_DETAIL_ID`
FOREIGN KEY (`id`)
REFERENCES `passport_detail` (`id`)
);Here, we will use Person and PassportDetail classes:
Source file: Person.java
@Entity
@Table(name = "person")
public class Person {
@Id
@GeneratedValue
@Column(name = "id")
private long id;
@Column(name = "name")
private String name;
@OneToOne(cascade = CascadeType.ALL)
@PrimaryKeyJoinColumn
private PassportDetail passportDetail;
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public PassportDetail getPassportDetail() {
return passportDetail;
}
public void setPassportDetail(PassportDetail passportDetail) {
this.passportDetail = passportDetail;
}
}Source file: PassportDetail.java
@Entity
@Table(name = "passport_detail")
public class PassportDetail {
@Id
@GeneratedValue
@Column(name = "id")
private long id;
@Column(name = "passportno")
private String passportNo;
@OneToOne(
mappedBy = "passportDetail"
, cascade = CascadeType.ALL
)
private Person person;
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getPassportNo() {
return passportNo;
}
public void setPassportNo(String passportNo) {
this.passportNo = passportNo;
}
public Person getPerson() {
return person;
}
public void setPerson(Person person) {
this.person = person;
}
}In this section, we will take a look at how to insert a record step by step.
Use the following code to insert a record in to the database. Here, we will insert a Person with a PassportDetail object:
PassportDetail detail = new PassportDetail();
detail.setPassportNo("G44244781");
Person person = new Person();
person.setId(1);
person.setName("Virendra");
person.setPassportDetail(detail);
Transaction transaction = session.getTransaction();
transaction.begin();
session.save(person);
transaction.commit();Let's start with the changes in the PassportDetail class.
The first change is in @OneToOne(cascade = CascadeType.ALL).
Here, we used @OneToOne with the CascadeType.ALL option, which informs hibernate to create a one-to-one relationship and apply cascading for all operations.
The changes in the Person class are as follows:
@PrimaryKeyJoinColumnprivate PassportDetail passportDetail;
The @PrimaryKeyJoinColumn annotation is used with the PassportDetail class, which creates a reference between the primary key of the Person class and the primary key of the PassportDetail class.