Hibernate Configuration

As Hibernate can operate in different environments, it requires a wide range of configuration parameters. These configurations contain the mapping information that provides different functionalities to Java classes. Generally, we provide database related mappings in the configuration file. Hibernate facilitates to provide the configurations either in an XML file (like hibernate.cfg.xml) or properties file (like hibernate.properties).

An instance of Configuration class allows specifying properties and mappings to applications. This class also builds an immutable SessionFactory.

We can acquire the Configuration class instance by instantiating it directly and specifying mappings in the configuration file. Use the addResource() method, if the mapping files are present in the classpath.

Configuration cfg = new Configuration()
    .addResource("employee.hbm.xml")

Let's see an example to provide the configurations in XML file and properties file.

XML Based Configuration

<?xml version="1.0" encoding="UTF-8"?>  
<!DOCTYPE hibernate-configuration PUBLIC  
        "-//Hibernate/Hibernate Configuration DTD 5.3//EN"  
        "http://www.hibernate.org/dtd/hibernate-configuration-5.3.dtd">  
<hibernate-configuration>  
    <session-factory>  
            
    <property name="hbm2ddl.auto">update</property>    
        <property name="dialect">org.hibernate.dialect.Oracle9Dialect</property>    
        <property name="connection.url">jdbc:oracle:thin:@localhost:1521:xe</property>    
        <property name="connection.username">system</property>    
        <property name="connection.password">jtp</property>    
        <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>   
       
    </session-factory>  
</hibernate-configuration>

Properties File Configuration

hibernate.dialect= org.hibernate.dialect.Oracle9Dialect
hibernate.connection.driver_class= oracle.jdbc.driver.OracleDriver
hibernate.connection.url= jdbc:oracle:thin:@localhost:1521:xe
hibernate.connection.username= system
hibernate.connection.password=jtp
hibernate.show_sql=true  
hibernate.hbm2ddl=update  

Properties of Hibernate Configuration

Hibernate JDBC Properties

Property	Description
hibernate.connection.driver_class	It represents the JDBC driver class.
hibernate.connection.url	It represents the JDBC URL.
hibernate.connection.username	It represents the database username.
hibernate.connection.password	It represents the database password.
Hibernate.connection.pool_size	It represents the maximum number of connections available in the connection pool.

Hibernate Datasource Properties

Property	Description
hibernate.connection.datasource	It represents datasource JNDI name which is used by Hibernate for database properties.
hibernate.jndi.url	It is optional. It represents the URL of the JNDI provider.
hibernate.jndi.class	It is optional. It represents the class of the JNDI InitialContextFactory.

Hibernate Configuration Properties

Property	Description
hibernate.dialect	It represents the type of database used in hibernate to generate SQL statements for a particular relational database.
hibernate.show_sql	It is used to display the executed SQL statements to console.
hibernate.format_sql	It is used to print the SQL in the log and console.
hibernate.default_catalog	It qualifies unqualified table names with the given catalog in generated SQL.
hibernate.default_schema	It qualifies unqualified table names with the given schema in generated SQL.
hibernate.session_factory_name	The SessionFactory interface automatically bound to this name in JNDI after it has been created.
hibernate.default_entity_mode	It sets a default mode for entity representation for all sessions opened from this SessionFactory
hibernate.order_updates	It orders SQL updates on the basis of the updated primary key.
hibernate.use_identifier_rollback	If enabled, the generated identifier properties will be reset to default values when objects are deleted.
hibernate.generate_statistics	If enabled, the Hibernate will collect statistics useful for performance tuning.
hibernate.use_sql_comments	If enabled, the Hibernate generate comments inside the SQL. It is used to make debugging easier.

Hibernate Cache Properties

Property	Description
hibernate.cache.provider_class	It represents the classname of a custom CacheProvider.
hibernate.cache.use_minimal_puts	It is used to optimize the second-level cache. It minimizes writes, at the cost of more frequent reads.
hibernate.cache.use_query_cache	It is used to enable the query cache.
hibernate.cache.use_second_level_cache	It is used to disable the second-level cache, which is enabled by default for classes which specify amapping.
hibernate.cache.query_cache_factory	It represents the classname of a custom QueryCache interface.
hibernate.cache.region_prefix	It specifies the prefix which is used for second-level cache region names.
hibernate.cache.use_structured_entries	It facilitates Hibernate to store data in the second-level cache in a more human-friendly format.

Hibernate Transaction Properties

Property	Description
hibernate.transaction.factory_class	It represents the classname of a TransactionFactory which is used with Hibernate Transaction API.
hibernate.transaction.manager_lookup_class	It represents the classname of a TransactionManagerLookup. It is required when JVM-level caching is enabled.
hibernate.transaction.flush_before_completion	If it is enabled, the session will be automatically flushed during the before completion phase of the transaction.
hibernate.transaction.auto_close_session	If it is enabled, the session will be automatically closed during the after completion phase of the transaction.

Other Hibernate Properties

Property	Description
hibernate.connection.provider_class	It represents the classname of a custom ConnectionProvider which provides JDBC connections to Hibernate.
hibernate.connection.isolation	It is used to set the JDBC transaction isolation level.
hibernate.connection.autocommit	It enables auto-commit for JDBC pooled connections. However, it is not recommended.
hibernate.connection.release_mode	It specifies when Hibernate should release JDBC connections.
hibernate.current_session_context_class	It provides a custom strategy for the scoping of the "current" Session.
hibernate.hbm2ddl.auto	It automatically generates a schema in the database with the creation of SessionFactory.