Delete All Records

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Delete All Records

In this section, you will learn how to delete all record using jpa.

In this section, you will learn how to delete all record using jpa.

Delete All Records

     

In this section, you will learn how to delete all record using jpa. You need the following artifacts:

  1. Database table: student
  2. Model Class: Student.java
  3. Main Class: JPADeleteAllRecords.java
  4. And its required jar files.

Table: student

CREATE TABLE `student` ( 
`id` int(11) NOT NULL auto_increment, 
`sname` varchar(40) NOT NULL, 
`sroll` int(11) NOT NULL, 
`scourse` varchar(10) default NULL, 
PRIMARY KEY (`id`) 
)

Model Class: Student.java

/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/

package jpacrud;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;

/**
*
* @author Administrator
*/
@Entity
@Table(name="student")

@NamedQueries({
@NamedQuery(name="readAllRecords",query="SELECT st FROM Student st"),
@NamedQuery(name="updateRecord",query="UPDATE Student st SET st.sname= ?1 WHERE st.sroll= ?2")
})
public class Student implements java.io.Serializable {

@Id
@GeneratedValue
private int id;

public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

@Column(name="sname",length=40,nullable=false)
private String sname;

public String getSname() {
return sname;
}

public void setSname(String sname) {
this.sname = sname;
}

@Column(name="sroll",nullable=false)
private int sroll;

public int getSroll() {
return sroll;
}

public void setSroll(int sroll) {
this.sroll = sroll;
}

@Column(name="scourse",length=10,nullable=true)
private String scourse;

public String getScourse() {
return scourse;
}

public void setScourse(String scourse) {
this.scourse = scourse;
}

}

Main Class: JPADeleteAllRecords.java

/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/

package jpacrud;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;
import javax.persistence.Query;

/**
*
* @author Administrator
*/
public class JPADeleteAllRecords {
public static void main(String arg[]){
EntityManagerFactory emf=Persistence.createEntityManagerFactory("netjpa");
EntityManager em=emf.createEntityManager();
try{
EntityTransaction entr=em.getTransaction();
entr.begin();
Query query=em.createQuery("DELETE FROM Student st");
int deleteRecords=query.executeUpdate();
entr.commit();
System.out.println("All records are deleted.");
}
catch(Exception ex){
System.out.println(ex.getMessage());
}
finally{
em.close();
}
}
}

Output:

init:
deps-jar:
compile-single:
run-single:
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.annotations.Version).
log4j:WARN Please initialize the log4j system properly.
Hibernate: delete from student
All records are deleted.
BUILD SUCCESSFUL (total time: 5 seconds)

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