JPA Native Queries
In this section, you will know about the jpa native queries and how to use native query in your JPA application.
JPA Native Queries: JPA native query executes plain SQL queries. JPA Native queries have the following properties:
- A native query returns either a single scalar value. Or
- It returns all persistent values to specified entity class.
For jpa native query application, you need develop the following artifacts:
- Database Table: student
- Model Class: Student.java
- Main Class: JPANativeQuery.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: JPANativeQuery.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 JPANativeQuery { /** * @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.createNativeQuery("SELECT sname FROM Student"); List stList=query.getResultList(); Iterator stIterator=stList.iterator(); while(stIterator.hasNext()){ System.out.print("sname:"+stIterator.next()); System.out.println(); } 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: SELECT sname FROM Student sname:Vinod sname:Ravi sname:Suman
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