Java Tutorial/JPA/Delete

EJB QL Delete Statement

File: Main.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();
  }
}

EJB QL Delete With Condition

File: Main.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();
  }
}

Remove a Found Entity

File: Student.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";
  }
}

Remove a Just Added Entity

File: Student.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";
  }
}