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Hibernate: Query Caching

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In this part you will learn about Hibernate query caching.

Hibernate: Query Caching

In this part you will learn about Hibernate query caching.

Query Caching :

Second type of cache is called the query cache and it is optional. Using this cache ,Hibernate cache queries and their results in the event the application executes the same query again.
The query cache takes memory and it is useful for queries that run frequently with the same parameters. The main objective of query caching is to maintain caching for results of queries.

For Query caching we use in our code -

query.setCacheable(true);

It defines that the query is actually cacheable. If we will not define it, then it would not be cached.
We should also do some changes in configuration file to enable the query cache.
Here is the property attribute to add in Hibernate.cfg.xml-

<property name="hibernate.cache.use_query_cache">true</property>

Example :

Hibernate.cfg.xml -

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

<session-factory>

<!-- Database connection settings -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost:3306/hibernate_examples</property>
<property name="connection.username">root</property>
<property name="connection.password">root</property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>
<!-- Enable Hibernate's query cache -->
<property name="hibernate.cache.use_query_cache">true</property>
<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">none</property>
<mapping class="net.roseindia.table.Student"/>
</session-factory>

</hibernate-configuration>

Main Class  HibernateQueryCache.java -

package net.roseindia.main;

import java.util.Iterator;

import net.roseindia.table.Student;
import net.roseindia.util.HibernateUtil;
import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;

public class HibernateQueryCache {
public static void main(String args[]) {
Session session = HibernateUtil.getSessionFactory().openSession();

try {
Query query = session.createQuery("FROM Student stud WHERE stud.roll=1");
query.setCacheable(true);   //Enabling query cache
Iterator iterator=query.list().iterator();
while(iterator.hasNext()){
Student student=(Student) iterator.next();
System.out.println("RollNo. :" + student.getRoll());
System.out.println("Name :" + student.getName());
System.out.println("Course :" + student.getCourse());
}


session.close();
} catch (HibernateException e) {
e.printStackTrace();
}
}
}

Click here to download complete source code

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Posted on: August 20, 2012

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Comments:1
bijendra
December 3, 2012
java

java is a better language
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