Java Tutorial/JPA/Delete

EJB QL Delete Statement

File: Main.java

   <source lang="java">

import java.util.List; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; public class Main {

 static EntityManagerFactory emf = Persistence.createEntityManagerFactory("JPAService");
 static EntityManager em = emf.createEntityManager();
 public static void main(String[] a) throws Exception {
   em.getTransaction().begin();
   em.createQuery("DELETE FROM Department d WHERE d.name IN ("CA13", "CA19", "NY30")")
       .executeUpdate();
   em.getTransaction().rumit();
   em.close();
   emf.close();
   Helper.checkData();
 }

}</source>

EJB QL Delete With Condition

File: Main.java

   <source lang="java">

import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; import javax.persistence.Query; public class Main {

 static EntityManagerFactory emf = Persistence.createEntityManagerFactory("JPAService");
 static EntityManager em = emf.createEntityManager();
 public static void main(String[] a) throws Exception {
   em.getTransaction().begin();
   Query query = em.createQuery("DELETE FROM Student e WHERE e.department IS NULL");
   query.executeUpdate();
   em.getTransaction().rumit();
   em.close();
   emf.close();
   Helper.checkData();
 }

}</source>

Remove a Found Entity

File: Student.java

   <source lang="java">

import java.util.Date; import javax.persistence.Entity; import javax.persistence.EnumType; import javax.persistence.Enumerated; import javax.persistence.Id; @Entity public class Student {

 @Id
 private long id = 0;
 private String name;
 private Date dateOfBirth = new Date();
 @Enumerated(EnumType.ORDINAL)
 private Gender gender;
 public Date getDateOfBirth() {
   return dateOfBirth;
 }
 public void setDateOfBirth(Date dateOfBirth) {
   this.dateOfBirth = dateOfBirth;
 }
 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 Gender getGender() {
   return gender;
 }
 public void setGender(Gender gender) {
   this.gender = gender;
 }
 public String toString() {
   return "\n\nID:" + id + "\nName:" + name + "\nBirthday:" + dateOfBirth + "\nGender:"
       + gender+"\n\n";
 }

}</source>

Remove a Just Added Entity

File: Student.java

   <source lang="java">

import java.util.Date; import javax.persistence.Entity; import javax.persistence.EnumType; import javax.persistence.Enumerated; import javax.persistence.Id; @Entity public class Student {

 @Id
 private long id = 0;
 private String name;
 private Date dateOfBirth = new Date();
 @Enumerated(EnumType.ORDINAL)
 private Gender gender;
 public Date getDateOfBirth() {
   return dateOfBirth;
 }
 public void setDateOfBirth(Date dateOfBirth) {
   this.dateOfBirth = dateOfBirth;
 }
 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 Gender getGender() {
   return gender;
 }
 public void setGender(Gender gender) {
   this.gender = gender;
 }
 public String toString() {
   return "\n\nID:" + id + "\nName:" + name + "\nBirthday:" + dateOfBirth + "\nGender:"
       + gender+"\n\n";
 }

}</source>