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JPA Concat Function
Posted on: June 13, 2009 at 12:00 AM

In this section, you will learn about the JPQL (Java Persistence Query Language) concat() function.

JPA Concat Function

In this section, you will learn about the JPQL (Java Persistence Query Language) concat() function. The concat() function concatenates two string fields or literals.

JPQL concat() Function:

Query query=em.createQuery("UPDATE Student st SET st.sname=CONCAT(st.sname,' kumar')");

This JPQL concatenates the string "kumar" to all sname field of student table.

For JPA Concat application, you need the following artifacts:

Database Table: student
Model Class: Student.java
Main Class: JPAConcatFunction.java

Database Table: student

CREATE TABLE `student` (
`id` int(11) NOT NULL auto_increment,
`sname` varchar(100) NOT NULL,
`sroll` int(11) NOT NULL,
`scourse` varchar(10) NOT NULL,
PRIMARY KEY (`id`)
)

Model Class: Student.java

/**
*
*/
package roseindia;

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")

public class Student {

@Id
@GeneratedValue
private int id;

/**
* @return the id
*/
public int getId() {
return id;
}

/**
* @param id the id to set
*/
public void setId(int id) {
this.id = id;
}

@Column(name="sname", length=100,nullable=false)
private String sname;

/**
* @return the sname
*/
public String getSname() {
return sname;
}

/**
* @param sname the sname to set
*/
public void setSname(String sname) {
this.sname = sname;
}

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

/**
* @return the sroll
*/
public int getSroll() {
return sroll;
}

/**
* @param sroll the sroll to set
*/
public void setSroll(int sroll) {
this.sroll = sroll;
}

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

/**
* @return the scourse
*/
public String getScourse() {
return scourse;
}

/**
* @param scourse the scourse to set
*/
public void setScourse(String scourse) {
this.scourse = scourse;
}

}

Main Class: JPAConcatFunction.java

/**
* 
*/
package roseindia;

import java.util.Iterator;
import java.util.List;

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

/**
* @author Administrator
*
*/
public class JPAConcatFunction {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
EntityManagerFactory emf=Persistence.createEntityManagerFactory("jpa");
EntityManager em=emf.createEntityManager();
try{
EntityTransaction entr=em.getTransaction();
entr.begin();
Query query=em.createQuery("UPDATE Student st SET st.sname=CONCAT(st.sname,' kumar')");
int updateRecord=query.executeUpdate();
System.out.println(updateRecord+" reocrds are updated");
entr.commit();
}
finally{
em.close();
}
}
}

Output:

log4j:WARN No appenders could be found for logger (org.hibernate.cfg.annotations.Version).

log4j:WARN Please initialize the log4j system properly.

Hibernate: update student set sname=concat(sname, ' kumar')

3 reocrds are updated

Before concatenation table data:

After concatenation table data:

Related Tags for JPA Concat Function:
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