Java Tutorial/JPA/Delete
Содержание
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>