One-To-Many Hibernate Mapping

One to Many Mapping: A single attribute of a table relating with multiple attributes of another table is referred as One to Many mapping. A department may have multiple employees.

1. Create Database Name is mapping and Two Table are employee1 and department.
CREATE TABLE `department` ( `department_id` BIGINT(20) NOT NULL AUTO_INCREMENT, `dept_name` VARCHAR(50) NOT NULL DEFAULT '0', PRIMARY KEY (`department_id`) ) COLLATE='latin1_swedish_ci' ENGINE=InnoDB ROW_FORMAT=DEFAULT AUTO_INCREMENT=115 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 NULL DEFAULT NULL, `cell_phone` VARCHAR(15) NULL DEFAULT NULL, `department_id` BIGINT(20) NULL DEFAULT NULL, PRIMARY KEY (`employee_id`), INDEX `FK_DEPT` (`department_id`), CONSTRAINT `FK_DEPT` FOREIGN KEY (`department_id`) REFERENCES `department` (`department_id`) ) COLLATE='latin1_swedish_ci' ENGINE=InnoDB ROW_FORMAT=DEFAULT
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 "OnetoManyMapping". 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> <property name="hibernate.show_sql">true</property> <mapping resource="onetomany/manoj/Employee1.hbm.xml"/> <mapping resource="onetomany/manoj/Department.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="employee1"/> <table-filter match-name="department"/> </hibernate-reverse-engineering>
4. Employee1.java
package onetomany.manoj; import java.util.Date; public class Employee1 implements java.io.Serializable { private Long employeeId; private Department department; private String firstname; private String lastname; private Date birthDate; private String cellPhone; public Employee1() { } public Employee1(Department department, String firstname, String lastname, Date birthDate, String cellPhone) { this.department = department; this.firstname = firstname; this.lastname = lastname; this.birthDate = birthDate; this.cellPhone = cellPhone; } public Long getEmployeeId() { return this.employeeId; } public void setEmployeeId(Long employeeId) { this.employeeId = employeeId; } public Department getDepartment() { return this.department; } public void setDepartment(Department department) { this.department = department; } 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; } }
5. Department.java
package onetomany.manoj; import java.util.HashSet; import java.util.Set; public class Department implements java.io.Serializable { private Long departmentId; private String deptName; private Set<employee1> employee1s = new HashSet<employee1>(0); public Department() { } public Department(String deptName) { this.deptName = deptName; } public Department(String deptName, Set<employee1> employee1s) { this.deptName = deptName; this.employee1s = employee1s; } public Long getDepartmentId() { return this.departmentId; } public void setDepartmentId(Long departmentId) { this.departmentId = departmentId; } public String getDeptName() { return this.deptName; } public void setDeptName(String deptName) { this.deptName = deptName; } public Set<employee1> getEmployee1s() { return this.employee1s; } public void setEmployee1s(Set<employee1> employee1s) { this.employee1s = employee1s; } }
6. Employee1.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 May 15, 2016 11:55:12 AM by Hibernate Tools 4.3.1 --> <hibernate-mapping> <class name="onetomany.manoj.Employee1" table="employee1" catalog="mapping" optimistic-lock="version"> <id name="employeeId" type="java.lang.Long"> <column name="employee_id" /> <generator class="identity" /> </id> <many-to-one name="department" class="onetomany.manoj.Department" fetch="select"> <column name="department_id" /> </many-to-one> <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" /> </property> <property name="cellPhone" type="string"> <column name="cell_phone" length="15" /> </property> </class> </hibernate-mapping>
7. Department.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 May 15, 2016 11:55:12 AM by Hibernate Tools 4.3.1 --> <hibernate-mapping> <class name="onetomany.manoj.Department" table="department" catalog="mapping" optimistic-lock="version"> <id name="departmentId" type="java.lang.Long"> <column name="department_id" /> <generator class="identity" /> </id> <property name="deptName" type="string"> <column name="dept_name" length="50" not-null="true" /> </property> <set name="employee1s" table="employee1" inverse="true" lazy="true" fetch="select"> <key> <column name="department_id" /> </key> <one-to-many class="onetomany.manoj.Employee1" /> </set> </class> </hibernate-mapping>
8. OnetoMany.java
package main.com; import java.util.Date; import onetomany.manoj.Department; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.cfg.Configuration; import onetomany.manoj.Employee1; /** * * @author manojkumar */ public class OnetoMany { 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(); Department department = new Department(); department.setDeptName("SoftwareS"); Employee1 emp1 = new Employee1(department,"manoj", "kumar", new Date(), "81200638"); session1.save(department); session1.save(emp1); session1.getTransaction().commit(); session1.close(); } }
OUTPUT: Hibernate: insert into mapping.department (dept_name) values (?) Hibernate: insert into mapping.employee1 (department_id, firstname, lastname, birth_date, cell_phone) values (?, ?, ?, ?, ?)