Hibernate - Configuration

Hibernate requires to know in advance — where to find the mapping information that defines how your Java classes relate to the database tables. Hibernate also requires a set of configuration settings related to database and other related parameters. All such information is usually supplied as a standard Java properties file called hibernate.properties, or as an XML file named hibernate.cfg.xml.

I will consider XML formatted file hibernate.cfg.xml to specify required Hibernate properties in my examples. Most of the properties take their default values and it is not required to specify them in the property file unless it is really required. This file is kept in the root directory of your application's classpath.

Hibernate Properties

Following is the list of important properties, you will be required to configure for a databases in a standalone situation −

If you are using a database along with an application server and JNDI, then you would have to configure the following properties −

Hibernate with MySQL Database

MySQL is one of the most popular open-source database systems available today. Let us create hibernate.cfg.xml configuration file and place it in the root of your application's classpath. You will have to make sure that you have testdb database available in your MySQL database and you have a user test available to access the database.

The XML configuration file must conform to the Hibernate 3 Configuration DTD, which is available at http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd.

<?xml version = "1.0" encoding = "utf-8"?>
<!DOCTYPE hibernate-configuration SYSTEM 
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
   <session-factory>
   
      <property name = "hibernate.dialect">
         org.hibernate.dialect.MySQLDialect
      </property>
      
      <property name = "hibernate.connection.driver_class">
         com.mysql.jdbc.Driver
      </property>
      
      <!-- Assume test is the database name -->
      
      <property name = "hibernate.connection.url">
         jdbc:mysql://localhost/test
      </property>
      
      <property name = "hibernate.connection.username">
         root
      </property>
      
      <property name = "hibernate.connection.password">
         root123
      </property>
      
      <!-- List of XML mapping files -->
      <mapping resource = "Employee.hbm.xml"/>
      
   </session-factory>
</hibernate-configuration>

The above configuration file includes <mapping> tags, which are related to hibernatemapping file and we will see in next chapter what exactly a hibernate mapping file is and how and why do we use it?

Following is the list of various important databases dialect property type −