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>