13. What are the important tags of hibernate.cfg.xml ?

Following are the important tags of hibernate.cfg.xml:

Property name	Purpose
hibernate.connection.driver_class	JDBC driver class
hibernate.connection.url	JDBC URL
hibernate.connection.username	database user
hibernate.connection.password	database user password
hibernate.connection.pool_size	maximum number of pooled connections

Hibernate Optional Configuration Properties

Property name	Purpose
hibernate.dialect	The classname of a Hibernate org.hibernate.dialect.Dialect which allows Hibernate to generate SQL optimized for a particular relational database. e.g. full.classname.of.Dialect In most cases Hibernate will actually be able to choose the correct org.hibernate.dialect.Dialect implementation based on the JDBC metadata returned by the JDBC driver.
hibernate.show_sql	Write all SQL statements to console. This is an alternative to setting the log category org.hibernate.SQL to debug. e.g. true | false
hibernate.format_sql	Pretty print the SQL in the log and console. e.g. true | false
hibernate.default_schema	Qualify unqualified table names with the given schema/tablespace in generated SQL. e.g. SCHEMA_NAME
hibernate.default_catalog	Qualifies unqualified table names with the given catalog in generated SQL. e.g. CATALOG_NAME
hibernate.session_factory_name	The org.hibernate.SessionFactory will be automatically bound to this name in JNDI after it has been created. e.g. jndi/composite/name
hibernate.max_fetch_depth	Sets a maximum "depth" for the outer join fetch tree for single-ended associations (one-to-one, many-to-one). A 0 disables default outer join fetching. e.g. recommended values between 0 and 3
hibernate.default_batch_fetch_size	Sets a default size for Hibernate batch fetching of associations. e.g. recommended values 4, 8, 16
hibernate.default_entity_mode	Sets a default mode for entity representation for all sessions opened from this SessionFactory dynamic-map, dom4j, pojo
hibernate.order_updates	Forces Hibernate to order SQL updates by the primary key value of the items being updated. This will result in fewer transaction deadlocks in highly concurrent systems. e.g. true | false
hibernate.generate_statistics	If enabled, Hibernate will collect statistics useful for performance tuning. e.g. true | false
hibernate.use_identifier_rollback	If enabled, generated identifier properties will be reset to default values when objects are deleted. e.g. true | false
hibernate.use_sql_comments	If turned on, Hibernate will generate comments inside the SQL, for easier debugging, defaults to false. e.g. true | false

Hibernate JDBC and Connection Properties

Property name	Purpose
hibernate.jdbc.fetch_size	A non-zero value determines the JDBC fetch size (calls Statement.setFetchSize()).
hibernate.jdbc.batch_size	A non-zero value enables use of JDBC2 batch updates by Hibernate. e.g. recommended values between 5 and 30
hibernate.jdbc.batch_versioned_data	Set this property to true if your JDBC driver returns correct row counts from executeBatch(). Iit is usually safe to turn this option on. Hibernate will then use batched DML for automatically versioned data. Defaults to false. e.g. true | false
hibernate.jdbc.factory_class	Select a custom org.hibernate.jdbc.Batcher. Most applications will not need this configuration property. e.g. classname.of.BatcherFactory
hibernate.jdbc.use_scrollable_resultset	Enables use of JDBC2 scrollable resultsets by Hibernate. This property is only necessary when using user-supplied JDBC connections. Hibernate uses connection metadata otherwise. e.g. true | false
hibernate.jdbc.use_streams_for_binary	Use streams when writing/reading binaryserializable types to/from JDBC. *system-level property* or e.g. true | false
hibernate.jdbc.use_get_generated_keys	Enables use of JDBC3 PreparedStatement.getGeneratedKeys() to retrieve natively generated keys after insert. Requires JDBC3+ driver and JRE1.4+, set to false if your driver has problems with the Hibernate identifier generators. By default, it tries to determine the driver capabilities using connection metadata. e.g. true|false
hibernate.connection.provider_class	The classname of a custom org.hibernate.connection.ConnectionProvider which provides JDBC connections to Hibernate. e.g. classname.of.ConnectionProvider
hibernate.connection.isolation	Sets the JDBC transaction isolation level. Check java.sql.Connection for meaningful values, but note that most databases do not support all isolation levels and some define additional, non-standard isolations. e.g. 1, 2, 4, 8
hibernate.connection.autocommit	Enables autocommit for JDBC pooled connections (it is not recommended). e.g. true | false
hibernate.connection.release_mode	Specifies when Hibernate should release JDBC connections. By default, a JDBC connection is held until the session is explicitly closed or disconnected. For an application server JTA datasource, use after_statement to aggressively release connections after every JDBC call. For a non-JTA connection, it often makes sense to release the connection at the end of each transaction, by using after_transaction. auto will choose after_statement for the JTA and CMT transaction strategies and after_transaction for the JDBC transaction strategy. e.g. auto (default) | on_close | after_transaction | after_statement This setting only affects Sessions returned from SessionFactory.openSession. For Sessions obtained through SessionFactory.getCurrentSession, the CurrentSessionContext implementation configured for use controls the connection release mode for those Sessions.
hibernate.connection.	Pass the JDBC property DriverManager.getConnection(). to
hibernate.jndi.	Pass the property to the JNDI InitialContextFactory.

Hibernate Cache Properties

Property name	Purpose
hibernate.cache.provider_class	The classname of a custom CacheProvider. e.g. classname.of.CacheProvider
hibernate.cache.use_minimal_puts	Optimizes second-level cache operation to minimize writes, at the cost of more frequent reads. This setting is most useful for clustered caches and, in Hibernate3, is enabled by default for clustered cache implementations. e.g. true|false
hibernate.cache.use_query_cache	Enables the query cache. Individual queries still have to be set cachable. e.g. true|false
hibernate.cache.use_second_level_cache	Can be used to completely disable the second level cache, which is enabled by default for classes which specify a mapping. e.g. true|false
hibernate.cache.query_cache_factory	The classname of a custom QueryCacheStandardQueryCache. interface, defaults to the built-in e.g. classname.of.QueryCache
hibernate.cache.region_prefix	A prefix to use for second-level cache region names. e.g. prefix
hibernate.cache.use_structured_entries	Forces Hibernate to store data in the second-level cache in a more human-friendly format. e.g. true|false

Hibernate Transaction Properties

Property name	Purpose
hibernate.transaction.factory_class	The classname of a TransactionFactory to use with Hibernate Transaction API (defaults to JDBCTransactionFactory). e.g. classname.of.TransactionFactory
jta.UserTransaction	A JNDI name used by JTATransactionFactory to obtain the JTA UserTransaction from the application server. e.g. jndi/composite/name
hibernate.transaction.manager_lookup_class	The classname of a TransactionManagerLookup. It is required when JVM-level caching is enabled or when using hilo generator in a JTA environment. e.g.classname.of.TransactionManagerLookup
hibernate.transaction.flush_before_completion	If enabled, the session will be automatically flushed during the before completion phase of the transaction. Built-in and automatic session context management is preferred. e.g. true | false
hibernate.transaction.auto_close_session	If enabled, the session will be automatically closed during the after completion phase of the transaction. Built-in and automatic session context management is preferred. e.g. true | false

Miscellaneous Properties

Property name	Purpose
hibernate.current_session_context_class	Supply a custom strategy for the scoping of the "current" Session. See Section 2.5, “Contextual sessions” for more information about the built-in strategies. e.g. jta | thread | managed | custom.Class
hibernate.query.factory_class	Chooses the HQL parser implementation. e.g. org.hibernate.hql.ast.ASTQueryTranslatorFactory or org.hibernate.hql.classic.ClassicQueryTranslatorFactory
hibernate.query.substitutions	Is used to map from tokens in Hibernate queries to SQL tokens (tokens might be function or literal names, for example). e.g. hqlLiteral=SQL_LITERAL, hqlFunction=SQLFUNC
hibernate.hbm2ddl.auto	Automatically validates or exports schema DDL to the database when the SessionFactory is created. With create-drop, the database schema will be dropped when the SessionFactory is closed explicitly. e.g. validate | update | create | create-drop
hibernate.cglib.use_reflection_optimizer	Enables the use of CGLIB instead of runtime reflection (System-level property). Reflection can sometimes be useful when troubleshooting. Hibernate always requires CGLIB even if you turn off the optimizer. You cannot set this property in hibernate.cfg.xml. e.g. true | false

SQL Dialects

Always set the hibernate.dialect property to the correct org.hibernate.dialect.Dialect subclass for your database. If you specify a dialect, Hibernate will use sensible defaults for some of the other properties listed above. This means that you will not have to specify them manually.

Hibernate SQL Dialects (hibernate.dialect)

RDBMS	Dialect
DB2	org.hibernate.dialect.DB2Dialect
DB2 AS/400	org.hibernate.dialect.DB2400Dialect
DB2 OS390	org.hibernate.dialect.DB2390Dialect
PostgreSQL	org.hibernate.dialect.PostgreSQLDialect
MySQL	org.hibernate.dialect.MySQLDialect
MySQL with InnoDB	org.hibernate.dialect.MySQLInnoDBDialect
MySQL with MyISAM	org.hibernate.dialect.MySQLMyISAMDialect
Oracle (any version)	org.hibernate.dialect.OracleDialect
Oracle 9i	org.hibernate.dialect.Oracle9iDialect
Oracle 10g	org.hibernate.dialect.Oracle10gDialect
Sybase	org.hibernate.dialect.SybaseDialect
Sybase Anywhere	org.hibernate.dialect.SybaseAnywhereDialect
Microsoft SQL Server	org.hibernate.dialect.SQLServerDialect
SAP DB	org.hibernate.dialect.SAPDBDialect
Informix	org.hibernate.dialect.InformixDialect
HypersonicSQL	org.hibernate.dialect.HSQLDialect
Ingres	org.hibernate.dialect.IngresDialect
Progress	org.hibernate.dialect.ProgressDialect
Mckoi SQL	org.hibernate.dialect.MckoiDialect
Interbase	org.hibernate.dialect.InterbaseDialect
Pointbase	org.hibernate.dialect.PointbaseDialect
FrontBase	org.hibernate.dialect.FrontbaseDialect
Firebird	org.hibernate.dialect.FirebirdDialect