One-To-One Hibernate Mapping

A one-to-one relationships occurs when one entity is related to exactly one occurrence in another entity. Thus, there will be one primary key which will be mapped with both the entities.
1. Create Database Name is mapping and Two Table are employee and employeedetail.
/* EMPLOYEE table */ CREATE TABLE `employee` ( `employee_id` BIGINT(10) NOT NULL AUTO_INCREMENT, `firstname` VARCHAR(50) NULL DEFAULT NULL, `lastname` VARCHAR(50) NULL DEFAULT NULL, `birth_date` DATE NOT NULL, `cell_phone` VARCHAR(15) NOT NULL, PRIMARY KEY (`employee_id`) ) COLLATE='latin1_swedish_ci' ENGINE=InnoDB ROW_FORMAT=DEFAULT AUTO_INCREMENT=216 /* EMPLOYEEDETAIL table */ CREATE TABLE `employeedetail` ( `employee_id` BIGINT(20) NOT NULL AUTO_INCREMENT, `street` VARCHAR(50) NULL DEFAULT NULL, `city` VARCHAR(50) NULL DEFAULT NULL, `state` VARCHAR(50) NULL DEFAULT NULL, `country` VARCHAR(50) NULL DEFAULT NULL, PRIMARY KEY (`employee_id`), CONSTRAINT `FKEMPL` FOREIGN KEY (`employee_id`) REFERENCES `employee` (`employee_id`) ) COLLATE='latin1_swedish_ci' ENGINE=InnoDB ROW_FORMAT=DEFAULT AUTO_INCREMENT=216
Open NetBeans See The Menu Bar go to the file Menu Click on the New Project(Ctrl+Shift+N) and Select Left site categories java web and Project categories to Right Site Project web Application .You have to give The Program Name "Mapping". if you wont to save Project Location you can Browse and File save on the direction place and Gone a default Place and Now uncheck/check the check box and click on the next button, select server settings and select the frameworks like Hibernate and go to the finish.

2. hibernate.cfg.xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property> <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/mapping?zeroDateTimeBehavior=convertToNull</property> <property name="hibernate.connection.username">root</property> <mapping resource="com/manoj/kumar/net/Employeedetail.hbm.xml"/> <mapping resource="com/manoj/kumar/net/Employee.hbm.xml"/> </session-factory> </hibernate-configuration>
3. hibernate.reveng.xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-reverse-engineering PUBLIC "-//Hibernate/Hibernate Reverse Engineering DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-reverse-engineering-3.0.dtd"> <hibernate-reverse-engineering> <schema-selection match-catalog="mapping"/> <table-filter match-name="employeedetail"/> <table-filter match-name="employee"/> </hibernate-reverse-engineering>
4. Employee.java
package com.manoj.kumar.net; import java.util.Date; /** * Employee generated by hbm2java */ public class Employee implements java.io.Serializable { private Long employeeId; private String firstname; private String lastname; private Date birthDate; private String cellPhone; private Employeedetail employeedetail; private ID id; public Employee(ID id) { this.id = id; } public ID getId() { return id; } public void setId(ID id) { this.id = id; } public Employee() { } public Employee(String firstname, String lastname, Date birthDate, String cellPhone) { this.firstname = firstname; this.lastname = lastname; this.birthDate = birthDate; this.cellPhone = cellPhone; } public Employee(Date birthDate, String cellPhone) { this.birthDate = birthDate; this.cellPhone = cellPhone; } public Employee(String firstname, String lastname, Date birthDate, String cellPhone, Employeedetail employeedetail) { this.firstname = firstname; this.lastname = lastname; this.birthDate = birthDate; this.cellPhone = cellPhone; this.employeedetail = employeedetail; } public Long getEmployeeId() { return this.employeeId; } public void setEmployeeId(Long employeeId) { this.employeeId = employeeId; } public String getFirstname() { return this.firstname; } public void setFirstname(String firstname) { this.firstname = firstname; } public String getLastname() { return this.lastname; } public void setLastname(String lastname) { this.lastname = lastname; } public Date getBirthDate() { return this.birthDate; } public void setBirthDate(Date birthDate) { this.birthDate = birthDate; } public String getCellPhone() { return this.cellPhone; } public void setCellPhone(String cellPhone) { this.cellPhone = cellPhone; } public Employeedetail getEmployeedetail() { return this.employeedetail; } public void setEmployeedetail(Employeedetail employeedetail) { this.employeedetail = employeedetail; } }
5. Employeedetail.java
package com.manoj.kumar.net; public class Employeedetail implements java.io.Serializable { private Long employeeId; private Employee employee; private String street; private String city; private String state; private String country; public Employeedetail() { } public Employeedetail(String street, String city, String state, String country) { this.street = street; this.city = city; this.state = state; this.country = country; } public Employeedetail(Employee employee) { this.employee = employee; } public Employeedetail(Employee employee, String street, String city, String state, String country) { this.employee = employee; this.street = street; this.city = city; this.state = state; this.country = country; } public Long getEmployeeId() { return this.employeeId; } public void setEmployeeId(Long employeeId) { this.employeeId = employeeId; } public Employee getEmployee() { return this.employee; } public void setEmployee(Employee employee) { this.employee = employee; } public String getStreet() { return this.street; } public void setStreet(String street) { this.street = street; } public String getCity() { return this.city; } public void setCity(String city) { this.city = city; } public String getState() { return this.state; } public void setState(String state) { this.state = state; } public String getCountry() { return this.country; } public void setCountry(String country) { this.country = country; } }
6. Employee.hbm.xml
<?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> <!-- Generated Apr 14, 2016 4:15:02 PM by Hibernate Tools 4.3.1 --> <hibernate-mapping> <class name="com.manoj.kumar.net.Employee" table="employee" catalog="mapping" optimistic-lock="version"> <id name="employeeId" type="java.lang.Long"> <column name="employee_id" /> <generator class="identity" > </generator> </id> <property name="firstname" type="string"> <column name="firstname" length="50" /> </property> <property name="lastname" type="string"> <column name="lastname" length="50" /> </property> <property name="birthDate" type="date"> <column name="birth_date" length="10" not-null="true" /> </property> <property name="cellPhone" type="string"> <column name="cell_phone" length="15" not-null="true" /> </property> <one-to-one name="employeedetail" class="com.manoj.kumar.net.Employeedetail"></one-to-one> <one-to-one name="id" class="com.manoj.kumar.net.ID"></one-to-one> </class> </hibernate-mapping>
7. Employeedetail.hbm.xml
<?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> <!-- Generated Apr 14, 2016 4:15:02 PM by Hibernate Tools 4.3.1 --> <hibernate-mapping> <class name="com.manoj.kumar.net.Employeedetail" table="employeedetail" catalog="mapping" optimistic-lock="version"> <id name="employeeId" type="java.lang.Long"> <column name="employee_id" /> <generator class="foreign"> <param name="property">employee</param> </generator> </id> <one-to-one name="employee" class="com.manoj.kumar.net.Employee" constrained="true"></one-to-one> <property name="street" type="string"> <column name="street" length="50" /> </property> <property name="city" type="string"> <column name="city" length="50" /> </property> <property name="state" type="string"> <column name="state" length="50" /> </property> <property name="country" type="string"> <column name="country" length="50" /> </property> </class> </hibernate-mapping>
8. OnetoOnemapping.java
package manoj.mapping.file; import java.util.Date; import java.util.List; import com.manoj.kumar.net.Employee; import com.manoj.kumar.net.Employeedetail; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.cfg.Configuration; import com.manoj.kumar.net.ID; /** * * @author manojkumar */ public class OnetoOnemapping { public static void main(String[] args) { Configuration cf=new Configuration(); cf.configure("hibernate.cfg.xml"); SessionFactory factory = cf.buildSessionFactory(); Session session1=factory.openSession(); session1.getTransaction().begin(); ID id1=new ID(); Employeedetail employeeDetail = new Employeedetail("15th Street", "New Delhi", "Delhi", "India"); Employee employee = new Employee("manoj", "kumar", new Date(), "114-857-965"); employee.setEmployeedetail(employeeDetail); employeeDetail.setEmployee(employee); id1.setEmp(employee); session1.save(employee); session1.save(employeeDetail); session1.save(id1); List<employee> employees = session1.createQuery("From Employee").list(); for (Employee employee1 : employees) { System.out.println(employee1.getFirstname() + " , " + employee1.getLastname() + ", " + employee1.getEmployeedetail()); } session1.getTransaction().commit(); session1.close(); } } 9. output- 
Hibernate: insert into mapping.employee (firstname, lastname, birth_date, cell_phone) values (?, ?, ?, ?) Hibernate: insert into mapping.employeedetail (street, city, state, country, employee_id) values (?, ?, ?, ?, ?) Hibernate: insert into mapping.id (employee_id) values (?)