Java Tutorial/JPA/Update

EJB QL Update 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("UPDATE Student e SET e.salary = 60 WHERE e.salary = 55");
   query.executeUpdate();
   em.getTransaction().rumit();
   em.close();
   emf.close();
   Helper.checkData();
 }

}</source>

Update an Entity from find method

File: Gender.java

   <source lang="java">

public enum Gender {

 MALE, FEMALE

}</source>

Use Entity Returned From Merge Operation

File: Student.java

   <source lang="java">

import javax.persistence.CascadeType; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.ManyToOne; @Entity public class Student {

   @Id
   private int id;
   private String name;
   

   public int getId() {
       return id;
   }
   
   public void setId(int id) {
       this.id = id;
   }
   
   public String getName() {
       return name;
   }
   
   public void setName(String name) {
       this.name = name;
   }

   public String toString() {
       return "Student id: " + getId() + " name: " + getName();
   }

}</source>