From f47cbced6f1aa2342f5b3ac83fb8c723f5efe86d Mon Sep 17 00:00:00 2001 From: Steve Ebersole Date: Thu, 14 Aug 2008 15:28:13 +0000 Subject: [PATCH] undo fixes for HHH-3080,HHH-3190,HHH-2976,HHH-3397 git-svn-id: https://svn.jboss.org/repos/hibernate/core/trunk@15066 1b8cb986-b30d-0410-93ca-fae66ebed9b2 --- .../docbook/en-US/content/configuration.xml | 3518 ++++++++--------- 1 file changed, 1759 insertions(+), 1759 deletions(-) diff --git a/documentation/manual/src/main/docbook/en-US/content/configuration.xml b/documentation/manual/src/main/docbook/en-US/content/configuration.xml index 196b6dc9aa..b87575d865 100644 --- a/documentation/manual/src/main/docbook/en-US/content/configuration.xml +++ b/documentation/manual/src/main/docbook/en-US/content/configuration.xml @@ -1,1759 +1,1759 @@ - - - - - - - Configuration - - - Because Hibernate is designed to operate in many different environments, there - are a large number of configuration parameters. Fortunately, most have sensible - default values and Hibernate is distributed with an example - hibernate.properties file in etc/ that shows - the various options. Just put the example file in your classpath and customize it. - - - - Programmatic configuration - - - An instance of org.hibernate.cfg.Configuration represents an entire set of mappings - of an application's Java types to an SQL database. The org.hibernate.cfg.Configuration - is used to build an (immutable) org.hibernate.SessionFactory. The mappings - are compiled from various XML mapping files. - - - - You may obtain a org.hibernate.cfg.Configuration instance by instantiating - it directly and specifying XML mapping documents. If the mapping files are in the classpath, - use addResource(): - - - - - - An alternative (sometimes better) way is to specify the mapped class, and - let Hibernate find the mapping document for you: - - - - - - Then Hibernate will look for mapping files named /org/hibernate/auction/Item.hbm.xml - and /org/hibernate/auction/Bid.hbm.xml in the classpath. This approach eliminates any - hardcoded filenames. - - - - A org.hibernate.cfg.Configuration also allows you to specify configuration - properties: - - - - - - This is not the only way to pass configuration properties to Hibernate. - The various options include: - - - - - - Pass an instance of java.util.Properties to - Configuration.setProperties(). - - - - - Place a file named hibernate.properties in a root directory of the classpath. - - - - - Set System properties using java -Dproperty=value. - - - - - Include <property> elements in - hibernate.cfg.xml (discussed later). - - - - - - hibernate.properties is the easiest approach if you want to get started quickly. - - - - The org.hibernate.cfg.Configuration is intended as a startup-time object, - to be discarded once a SessionFactory is created. - - - - - - Obtaining a SessionFactory - - - When all mappings have been parsed by the org.hibernate.cfg.Configuration, - the application must obtain a factory for org.hibernate.Session instances. - This factory is intended to be shared by all application threads: - - - - - - Hibernate does allow your application to instantiate more than one - org.hibernate.SessionFactory. This is useful if you are using more than - one database. - - - - - - JDBC connections - - - Usually, you want to have the org.hibernate.SessionFactory create and pool - JDBC connections for you. If you take this approach, opening a org.hibernate.Session - is as simple as: - - - - - - As soon as you do something that requires access to the database, a JDBC connection will be obtained from - the pool. - - - - For this to work, we need to pass some JDBC connection properties to Hibernate. All Hibernate property - names and semantics are defined on the class org.hibernate.cfg.Environment. We will - now describe the most important settings for JDBC connection configuration. - - - - Hibernate will obtain (and pool) connections using java.sql.DriverManager - if you set the following properties: - - - - Hibernate JDBC Properties - - - - - - 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's own connection pooling algorithm is however quite rudimentary. - It is intended to help you get started and is not intended for use - in a production system or even for performance testing. You should - use a third party pool for best performance and stability. Just replace the - hibernate.connection.pool_size property with connection - pool specific settings. This will turn off Hibernate's internal pool. For - example, you might like to use C3P0. - - - - C3P0 is an open source JDBC connection pool distributed along with Hibernate in the lib - directory. Hibernate will use its org.hibernate.connection.C3P0ConnectionProvider - for connection pooling if you set hibernate.c3p0.* properties. If you'd like to use Proxool - refer to the packaged hibernate.properties and the Hibernate web site for more - information. - - - - Here is an example hibernate.properties file for C3P0: - - - - - - For use inside an application server, you should almost always configure Hibernate to obtain connections - from an application server javax.sql.Datasource registered in JNDI. You'll - need to set at least one of the following properties: - - - - Hibernate Datasource Properties - - - - - - Property name - Purpose - - - - - - hibernate.connection.datasource - - - datasource JNDI name - - - - - hibernate.jndi.url - - - URL of the JNDI provider (optional) - - - - - hibernate.jndi.class - - - class of the JNDI InitialContextFactory (optional) - - - - - hibernate.connection.username - - - database user (optional) - - - - - hibernate.connection.password - - - database user password (optional) - - - - -
- - - Here's an example hibernate.properties file for an application server provided JNDI - datasource: - - - - - - JDBC connections obtained from a JNDI datasource will automatically participate - in the container-managed transactions of the application server. - - - - Arbitrary connection properties may be given by prepending "hibernate.connection" to the - connection property name. For example, you may specify a charSet - connection property using hibernate.connection.charSet. - - - - You may define your own plugin strategy for obtaining JDBC connections by implementing the - interface org.hibernate.connection.ConnectionProvider, and specifying your - custom implementation via the hibernate.connection.provider_class property. - - - - - - Optional configuration properties - - - There are a number of other properties that control the behaviour of Hibernate at runtime. All are optional - and have reasonable default values. - - - - Warning: some of these properties are "system-level" only. System-level properties can - be set only via java -Dproperty=value or hibernate.properties. They - may not be set by the other techniques described above. - - - - Hibernate 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. - - eg. - full.classname.of.Dialect - - - In most cases Hibernate will actually be able to chose the correct - org.hibernate.dialect.Dialect implementation to use 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. - - eg. - true | false - - - - - - hibernate.format_sql - - - Pretty print the SQL in the log and console. - - eg. - true | false - - - - - - hibernate.default_schema - - - Qualify unqualified table names with the given schema/tablespace - in generated SQL. - - eg. - SCHEMA_NAME - - - - - - hibernate.default_catalog - - - Qualify unqualified table names with the given catalog - in generated SQL. - - eg. - CATALOG_NAME - - - - - - hibernate.session_factory_name - - - The org.hibernate.SessionFactory will be automatically - bound to this name in JNDI after it has been created. - - eg. - jndi/composite/name - - - - - - hibernate.max_fetch_depth - - - Set 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. - - eg. - recommended values between 0 and - 3 - - - - - - hibernate.default_batch_fetch_size - - - Set a default size for Hibernate batch fetching of associations. - - eg. - recommended values 4, 8, - 16 - - - - - - hibernate.default_entity_mode - - - Set a default mode for entity representation for all sessions - opened from this SessionFactory - - dynamic-map, dom4j, - pojo - - - - - - hibernate.order_updates - - - Force 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. - - eg. - true | false - - - - - - hibernate.generate_statistics - - - If enabled, Hibernate will collect statistics useful for - performance tuning. - - eg. - true | false - - - - - - hibernate.use_identifier_rollback - - - If enabled, generated identifier properties will be - reset to default values when objects are deleted. - - eg. - true | false - - - - - - hibernate.use_sql_comments - - - If turned on, Hibernate will generate comments inside the SQL, for - easier debugging, defaults to false. - - eg. - 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. - - eg. - 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() (it is usually - safe to turn this option on). Hibernate will then use batched DML for - automatically versioned data. Defaults to false. - - eg. - true | false - - - - - - hibernate.jdbc.factory_class - - - Select a custom org.hibernate.jdbc.Batcher. Most applications - will not need this configuration property. - - eg. - 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. - - eg. - true | false - - - - - - hibernate.jdbc.use_streams_for_binary - - - Use streams when writing/reading binary or serializable - types to/from JDBC. *system-level property* - - eg. - true | false - - - - - - hibernate.jdbc.use_get_generated_keys - - - Enable 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, tries to determine the driver capabilities - using connection metadata. - - eg. - true|false - - - - - - hibernate.connection.provider_class - - - The classname of a custom org.hibernate.connection.ConnectionProvider - which provides JDBC connections to Hibernate. - - eg. - classname.of.ConnectionProvider - - - - - - hibernate.connection.isolation - - - Set 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. - - eg. - 1, 2, 4, 8 - - - - - - hibernate.connection.autocommit - - - Enables autocommit for JDBC pooled connections (not recommended). - - eg. - true | false - - - - - - hibernate.connection.release_mode - - - Specify 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, you should 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. - - eg. - auto (default) | on_close | - after_transaction | after_statement - - - Note that 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. - See - - - - - - hibernate.connection.<propertyName> - - - Pass the JDBC property <propertyName> - to DriverManager.getConnection(). - - - - - hibernate.jndi.<propertyName> - - - Pass the property <propertyName> to - the JNDI InitialContextFactory. - - - - -
- - - Hibernate Cache Properties - - - - - - Property name - Purpose - - - - - - hibernate.cache.provider_class - - - The classname of a custom CacheProvider. - - eg. - classname.of.CacheProvider - - - - - - hibernate.cache.use_minimal_puts - - - Optimize 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. - - eg. - true|false - - - - - - hibernate.cache.use_query_cache - - - Enable the query cache, individual queries still have to be set cachable. - - eg. - true|false - - - - - - hibernate.cache.use_second_level_cache - - - May be used to completely disable the second level cache, which is enabled - by default for classes which specify a <cache> - mapping. - - eg. - true|false - - - - - - hibernate.cache.query_cache_factory - - - The classname of a custom QueryCache interface, - defaults to the built-in StandardQueryCache. - - eg. - classname.of.QueryCache - - - - - - hibernate.cache.region_prefix - - - A prefix to use for second-level cache region names. - - eg. - prefix - - - - - - hibernate.cache.use_structured_entries - - - Forces Hibernate to store data in the second-level cache - in a more human-friendly format. - - eg. - 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). - - eg. - classname.of.TransactionFactory - - - - - - jta.UserTransaction - - - A JNDI name used by JTATransactionFactory to - obtain the JTA UserTransaction from the - application server. - - eg. - jndi/composite/name - - - - - - hibernate.transaction.manager_lookup_class - - - The classname of a TransactionManagerLookup - - required when JVM-level caching is enabled or when using hilo - generator in a JTA environment. - - eg. - 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, see - . - - eg. - 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 - utomatic session context management is preferred, see - . - - eg. - true | false - - - - - -
- - - Miscellaneous Properties - - - - - - Property name - Purpose - - - - - - hibernate.current_session_context_class - - - Supply a (custom) strategy for the scoping of the "current" - Session. See - for more - information about the built-in strategies. - - eg. - jta | thread | - managed | custom.Class - - - - - - hibernate.query.factory_class - - - Chooses the HQL parser implementation. - - eg. - org.hibernate.hql.ast.ASTQueryTranslatorFactory or - org.hibernate.hql.classic.ClassicQueryTranslatorFactory - - - - - - hibernate.query.substitutions - - - Mapping from tokens in Hibernate queries to SQL tokens - (tokens might be function or literal names, for example). - - eg. - hqlLiteral=SQL_LITERAL, hqlFunction=SQLFUNC - - - - - - hibernate.hbm2ddl.auto - - - Automatically validate or export 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. - - eg. - validate | update | - create | create-drop - - - - - - hibernate.cglib.use_reflection_optimizer - - - Enables use of CGLIB instead of runtime reflection (System-level - property). Reflection can sometimes be useful when troubleshooting, - note that Hibernate always requires CGLIB even if you turn off the - optimizer. You can not set this property in hibernate.cfg.xml. - - eg. - true | false - - - - - -
- - - SQL Dialects - - - You should 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, saving you the effort of specifying them manually. - - - - Hibernate SQL Dialects (<literal>hibernate.dialect</literal>) - - - - - 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/10g org.hibernate.dialect.Oracle9Dialect - - - 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 - - - -
- - - - - Outer Join Fetching - - - If your database supports ANSI, Oracle or Sybase style outer joins, outer join - fetching will often increase performance by limiting the number of round - trips to and from the database (at the cost of possibly more work performed by - the database itself). Outer join fetching allows a whole graph of objects connected - by many-to-one, one-to-many, many-to-many and one-to-one associations to be retrieved - in a single SQL SELECT. - - - - Outer join fetching may be disabled globally by setting - the property hibernate.max_fetch_depth to 0. - A setting of 1 or higher enables outer join fetching for - one-to-one and many-to-one associations which have been mapped with - fetch="join". - - - - See for more information. - - - - - - Binary Streams - - - Oracle limits the size of byte arrays that may - be passed to/from its JDBC driver. If you wish to use large instances of - binary or serializable type, you should - enable hibernate.jdbc.use_streams_for_binary. - This is a system-level setting only. - - - - - - Second-level and query cache - - - The properties prefixed by hibernate.cache - allow you to use a process or cluster scoped second-level cache system - with Hibernate. See the for - more details. - - - - - - Query Language Substitution - - - You may define new Hibernate query tokens using hibernate.query.substitutions. - For example: - - - hibernate.query.substitutions true=1, false=0 - - - would cause the tokens true and false to be translated to - integer literals in the generated SQL. - - - hibernate.query.substitutions toLowercase=LOWER - - - would allow you to rename the SQL LOWER function. - - - - - - Hibernate statistics - - - If you enable hibernate.generate_statistics, Hibernate will - expose a number of metrics that are useful when tuning a running system via - SessionFactory.getStatistics(). Hibernate can even be configured - to expose these statistics via JMX. Read the Javadoc of the interfaces in - org.hibernate.stats for more information. - - - - - - - Logging - - - Hibernate Annotations utilizes Simple Logging Facade for Java - (SLF4J) in order to log various system events. SLF4J can direct your logging output to - several logging frameworks (NOP, Simple, log4j version 1.2, JDK 1.4 logging, JCL or logback) depending on your - chosen binding. In order to setup logging properly you will need slf4j-api.jar in - your classpath together with the jar file for your preferred binding - slf4j-log4j12.jar - in the case of Log4J. See the SLF4J documentation for more detail. - To use Log4j you will also need to place a log4j.properties file in your classpath, - an example properties file is distributed with Hibernate in the src/ directory. - - - - We strongly recommend that you familiarize yourself with Hibernate's log - messages. A lot of work has been put into making the Hibernate log as - detailed as possible, without making it unreadable. It is an essential - troubleshooting device. The most interesting log categories are the - following: - - - - Hibernate Log Categories - - - - - - Category - Function - - - - - org.hibernate.SQL - Log all SQL DML statements as they are executed - - - org.hibernate.type - Log all JDBC parameters - - - org.hibernate.tool.hbm2ddl - Log all SQL DDL statements as they are executed - - - org.hibernate.pretty - - Log the state of all entities (max 20 entities) associated - with the session at flush time - - - - org.hibernate.cache - Log all second-level cache activity - - - org.hibernate.transaction - Log transaction related activity - - - org.hibernate.jdbc - Log all JDBC resource acquisition - - - org.hibernate.hql.ast.AST - - Log HQL and SQL ASTs during query parsing - - - - org.hibernate.secure - Log all JAAS authorization requests - - - org.hibernate - - Log everything (a lot of information, but very useful for - troubleshooting) - - - - -
- - - When developing applications with Hibernate, you should almost always work with - debug enabled for the category org.hibernate.SQL, - or, alternatively, the property hibernate.show_sql enabled. - - - - - - - Implementing a <literal>NamingStrategy</literal> - - - The interface org.hibernate.cfg.NamingStrategy allows you - to specify a "naming standard" for database objects and schema elements. - - - - You may provide rules for automatically generating database identifiers from - Java identifiers or for processing "logical" column and table names given in - the mapping file into "physical" table and column names. This feature helps - reduce the verbosity of the mapping document, eliminating repetitive noise - (TBL_ prefixes, for example). The default strategy used by - Hibernate is quite minimal. - - - - You may specify a different strategy by calling - Configuration.setNamingStrategy() before adding mappings: - - - - - - org.hibernate.cfg.ImprovedNamingStrategy is a built-in - strategy that might be a useful starting point for some applications. - - - - - - XML configuration file - - - An alternative approach to configuration is to specify a full configuration in - a file named hibernate.cfg.xml. This file can be used as a - replacement for the hibernate.properties file or, if both - are present, to override properties. - - - - The XML configuration file is by default expected to be in the root o - your CLASSPATH. Here is an example: - - - - - - - - - - - - java:/comp/env/jdbc/MyDB - org.hibernate.dialect.MySQLDialect - false - - org.hibernate.transaction.JTATransactionFactory - - java:comp/UserTransaction - - - - - - - - - - - - -]]> - - - As you can see, the advantage of this approach is the externalization of the - mapping file names to configuration. The hibernate.cfg.xml - is also more convenient once you have to tune the Hibernate cache. Note that is - your choice to use either hibernate.properties or - hibernate.cfg.xml, both are equivalent, except for the above - mentioned benefits of using the XML syntax. - - - - With the XML configuration, starting Hibernate is then as simple as - - - - - - You can pick a different XML configuration file using - - - - - - - - J2EE Application Server integration - - - Hibernate has the following integration points for J2EE infrastructure: - - - - - - Container-managed datasources: Hibernate can use - JDBC connections managed by the container and provided through JNDI. Usually, - a JTA compatible TransactionManager and a - ResourceManager take care of transaction management (CMT), - esp. distributed transaction handling across several datasources. You may - of course also demarcate transaction boundaries programmatically (BMT) or - you might want to use the optional Hibernate Transaction - API for this to keep your code portable. - - - - - - - - Automatic JNDI binding: Hibernate can bind its - SessionFactory to JNDI after startup. - - - - - - - - JTA Session binding: The Hibernate Session - may be automatically bound to the scope of JTA transactions. Simply - lookup the SessionFactory from JNDI and get the current - Session. Let Hibernate take care of flushing and closing the - Session when your JTA transaction completes. Transaction - demarcation is either declarative (CMT) or programmatic (BMT/UserTransaction). - - - - - - - - JMX deployment: If you have a JMX capable application server - (e.g. JBoss AS), you can chose to deploy Hibernate as a managed MBean. This saves - you the one line startup code to build your SessionFactory from - a Configuration. The container will startup your - HibernateService, and ideally also take care of service - dependencies (Datasource has to be available before Hibernate starts, etc). - - - - - - Depending on your environment, you might have to set the configuration option - hibernate.connection.aggressive_release to true if your - application server shows "connection containment" exceptions. - - - - Transaction strategy configuration - - - The Hibernate Session API is independent of any transaction - demarcation system in your architecture. If you let Hibernate use JDBC directly, - through a connection pool, you may begin and end your transactions by calling - the JDBC API. If you run in a J2EE application server, you might want to use bean-managed - transactions and call the JTA API and UserTransaction when needed. - - - - To keep your code portable between these two (and other) environments we recommend the optional - Hibernate Transaction API, which wraps and hides the underlying system. - You have to specify a factory class for Transaction instances by setting the - Hibernate configuration property hibernate.transaction.factory_class. - - - - There are three standard (built-in) choices: - - - - - org.hibernate.transaction.JDBCTransactionFactory - - delegates to database (JDBC) transactions (default) - - - - org.hibernate.transaction.JTATransactionFactory - - - delegates to container-managed transaction if an existing transaction is - underway in this context (e.g. EJB session bean method), otherwise - a new transaction is started and bean-managed transaction are used. - - - - - org.hibernate.transaction.CMTTransactionFactory - - delegates to container-managed JTA transactions - - - - - - You may also define your own transaction strategies (for a CORBA transaction service, - for example). - - - - Some features in Hibernate (i.e. the second level cache, Contextual Sessions with JTA, etc.) - require access to the JTA TransactionManager in a managed environment. - In an application server you have to specify how Hibernate should obtain a reference to the - TransactionManager, since J2EE does not standardize a single mechanism: - - - - JTA TransactionManagers - - - - - - Transaction Factory - Application Server - - - - - org.hibernate.transaction.JBossTransactionManagerLookup - JBoss - - - org.hibernate.transaction.WeblogicTransactionManagerLookup - Weblogic - - - org.hibernate.transaction.WebSphereTransactionManagerLookup - WebSphere - - - org.hibernate.transaction.WebSphereExtendedJTATransactionLookup - WebSphere 6 - - - org.hibernate.transaction.OrionTransactionManagerLookup - Orion - - - org.hibernate.transaction.ResinTransactionManagerLookup - Resin - - - org.hibernate.transaction.JOTMTransactionManagerLookup - JOTM - - - org.hibernate.transaction.JOnASTransactionManagerLookup - JOnAS - - - org.hibernate.transaction.JRun4TransactionManagerLookup - JRun4 - - - org.hibernate.transaction.BESTransactionManagerLookup - Borland ES - - - -
- - - - - JNDI-bound <literal>SessionFactory</literal> - - - A JNDI bound Hibernate SessionFactory can simplify the lookup - of the factory and the creation of new Sessions. Note that this - is not related to a JNDI bound Datasource, both simply use the - same registry! - - - - If you wish to have the SessionFactory bound to a JNDI namespace, specify - a name (eg. java:hibernate/SessionFactory) using the property - hibernate.session_factory_name. If this property is omitted, the - SessionFactory will not be bound to JNDI. (This is especially useful in - environments with a read-only JNDI default implementation, e.g. Tomcat.) - - - - When binding the SessionFactory to JNDI, Hibernate will use the values of - hibernate.jndi.url, hibernate.jndi.class to instantiate - an initial context. If they are not specified, the default InitialContext - will be used. - - - - Hibernate will automatically place the SessionFactory in JNDI after - you call cfg.buildSessionFactory(). This means you will at least have - this call in some startup code (or utility class) in your application, unless you use - JMX deployment with the HibernateService (discussed later). - - - - If you use a JNDI SessionFactory, an EJB or any other class may - obtain the SessionFactory using a JNDI lookup. - - - - We recommend that you bind the SessionFactory to JNDI in - a managed environment and use a static singleton otherwise. - To shield your application code from these details, we also recommend to hide the - actual lookup code for a SessionFactory in a helper class, - such as HibernateUtil.getSessionFactory(). Note that such a - class is also a convenient way to startup Hibernate—see chapter 1. - - - - - - Current Session context management with JTA - - - The easiest way to handle Sessions and transactions is - Hibernates automatic "current" Session management. - See the discussion of current sessions. - Using the "jta" session context, if there is no Hibernate - Session associated with the current JTA transaction, one will - be started and associated with that JTA transaction the first time you call - sessionFactory.getCurrentSession(). The Sessions - retrieved via getCurrentSession() in "jta" context - will be set to automatically flush before the transaction completes, close - after the transaction completes, and aggressively release JDBC connections - after each statement. This allows the Sessions to - be managed by the life cycle of the JTA transaction to which it is associated, - keeping user code clean of such management concerns. Your code can either use - JTA programmatically through UserTransaction, or (recommended - for portable code) use the Hibernate Transaction API to set - transaction boundaries. If you run in an EJB container, declarative transaction - demarcation with CMT is preferred. - - - - - - JMX deployment - - - The line cfg.buildSessionFactory() still has to be executed - somewhere to get a SessionFactory into JNDI. You can do this - either in a static initializer block (like the one in - HibernateUtil) or you deploy Hibernate as a managed - service. - - - - Hibernate is distributed with org.hibernate.jmx.HibernateService - for deployment on an application server with JMX capabilities, such as JBoss AS. - The actual deployment and configuration is vendor specific. Here is an example - jboss-service.xml for JBoss 4.0.x: - - - - - - - - - jboss.jca:service=RARDeployer - jboss.jca:service=LocalTxCM,name=HsqlDS - - - java:/hibernate/SessionFactory - - - java:HsqlDS - org.hibernate.dialect.HSQLDialect - - - - org.hibernate.transaction.JTATransactionFactory - - org.hibernate.transaction.JBossTransactionManagerLookup - true - true - - - 5 - - - true - org.hibernate.cache.EhCacheProvider - true - - - true - - - auction/Item.hbm.xml,auction/Category.hbm.xml - - - -]]> - - - This file is deployed in a directory called META-INF and packaged - in a JAR file with the extension .sar (service archive). You also need - to package Hibernate, its required third-party libraries, your compiled persistent classes, - as well as your mapping files in the same archive. Your enterprise beans (usually session - beans) may be kept in their own JAR file, but you may include this EJB JAR file in the - main service archive to get a single (hot-)deployable unit. Consult the JBoss AS - documentation for more information about JMX service and EJB deployment. - - - - - - - - + + + + + + + Configuration + + + Because Hibernate is designed to operate in many different environments, there + are a large number of configuration parameters. Fortunately, most have sensible + default values and Hibernate is distributed with an example + hibernate.properties file in etc/ that shows + the various options. Just put the example file in your classpath and customize it. + + + + Programmatic configuration + + + An instance of org.hibernate.cfg.Configuration represents an entire set of mappings + of an application's Java types to an SQL database. The org.hibernate.cfg.Configuration + is used to build an (immutable) org.hibernate.SessionFactory. The mappings + are compiled from various XML mapping files. + + + + You may obtain a org.hibernate.cfg.Configuration instance by instantiating + it directly and specifying XML mapping documents. If the mapping files are in the classpath, + use addResource(): + + + + + + An alternative (sometimes better) way is to specify the mapped class, and + let Hibernate find the mapping document for you: + + + + + + Then Hibernate will look for mapping files named /org/hibernate/auction/Item.hbm.xml + and /org/hibernate/auction/Bid.hbm.xml in the classpath. This approach eliminates any + hardcoded filenames. + + + + A org.hibernate.cfg.Configuration also allows you to specify configuration + properties: + + + + + + This is not the only way to pass configuration properties to Hibernate. + The various options include: + + + + + + Pass an instance of java.util.Properties to + Configuration.setProperties(). + + + + + Place a file named hibernate.properties in a root directory of the classpath. + + + + + Set System properties using java -Dproperty=value. + + + + + Include <property> elements in + hibernate.cfg.xml (discussed later). + + + + + + hibernate.properties is the easiest approach if you want to get started quickly. + + + + The org.hibernate.cfg.Configuration is intended as a startup-time object, + to be discarded once a SessionFactory is created. + + + + + + Obtaining a SessionFactory + + + When all mappings have been parsed by the org.hibernate.cfg.Configuration, + the application must obtain a factory for org.hibernate.Session instances. + This factory is intended to be shared by all application threads: + + + + + + Hibernate does allow your application to instantiate more than one + org.hibernate.SessionFactory. This is useful if you are using more than + one database. + + + + + + JDBC connections + + + Usually, you want to have the org.hibernate.SessionFactory create and pool + JDBC connections for you. If you take this approach, opening a org.hibernate.Session + is as simple as: + + + + + + As soon as you do something that requires access to the database, a JDBC connection will be obtained from + the pool. + + + + For this to work, we need to pass some JDBC connection properties to Hibernate. All Hibernate property + names and semantics are defined on the class org.hibernate.cfg.Environment. We will + now describe the most important settings for JDBC connection configuration. + + + + Hibernate will obtain (and pool) connections using java.sql.DriverManager + if you set the following properties: + + + + Hibernate JDBC Properties + + + + + + 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's own connection pooling algorithm is however quite rudimentary. + It is intended to help you get started and is not intended for use + in a production system or even for performance testing. You should + use a third party pool for best performance and stability. Just replace the + hibernate.connection.pool_size property with connection + pool specific settings. This will turn off Hibernate's internal pool. For + example, you might like to use C3P0. + + + + C3P0 is an open source JDBC connection pool distributed along with Hibernate in the lib + directory. Hibernate will use its org.hibernate.connection.C3P0ConnectionProvider + for connection pooling if you set hibernate.c3p0.* properties. If you'd like to use Proxool + refer to the packaged hibernate.properties and the Hibernate web site for more + information. + + + + Here is an example hibernate.properties file for C3P0: + + + + + + For use inside an application server, you should almost always configure Hibernate to obtain connections + from an application server javax.sql.Datasource registered in JNDI. You'll + need to set at least one of the following properties: + + + + Hibernate Datasource Properties + + + + + + Property name + Purpose + + + + + + hibernate.connection.datasource + + + datasource JNDI name + + + + + hibernate.jndi.url + + + URL of the JNDI provider (optional) + + + + + hibernate.jndi.class + + + class of the JNDI InitialContextFactory (optional) + + + + + hibernate.connection.username + + + database user (optional) + + + + + hibernate.connection.password + + + database user password (optional) + + + + +
+ + + Here's an example hibernate.properties file for an application server provided JNDI + datasource: + + + + + + JDBC connections obtained from a JNDI datasource will automatically participate + in the container-managed transactions of the application server. + + + + Arbitrary connection properties may be given by prepending "hibernate.connection" to the + connection property name. For example, you may specify a charSet + connection property using hibernate.connection.charSet. + + + + You may define your own plugin strategy for obtaining JDBC connections by implementing the + interface org.hibernate.connection.ConnectionProvider, and specifying your + custom implementation via the hibernate.connection.provider_class property. + + + + + + Optional configuration properties + + + There are a number of other properties that control the behaviour of Hibernate at runtime. All are optional + and have reasonable default values. + + + + Warning: some of these properties are "system-level" only. System-level properties can + be set only via java -Dproperty=value or hibernate.properties. They + may not be set by the other techniques described above. + + + + Hibernate 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. + + eg. + full.classname.of.Dialect + + + In most cases Hibernate will actually be able to chose the correct + org.hibernate.dialect.Dialect implementation to use 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. + + eg. + true | false + + + + + + hibernate.format_sql + + + Pretty print the SQL in the log and console. + + eg. + true | false + + + + + + hibernate.default_schema + + + Qualify unqualified table names with the given schema/tablespace + in generated SQL. + + eg. + SCHEMA_NAME + + + + + + hibernate.default_catalog + + + Qualify unqualified table names with the given catalog + in generated SQL. + + eg. + CATALOG_NAME + + + + + + hibernate.session_factory_name + + + The org.hibernate.SessionFactory will be automatically + bound to this name in JNDI after it has been created. + + eg. + jndi/composite/name + + + + + + hibernate.max_fetch_depth + + + Set 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. + + eg. + recommended values between 0 and + 3 + + + + + + hibernate.default_batch_fetch_size + + + Set a default size for Hibernate batch fetching of associations. + + eg. + recommended values 4, 8, + 16 + + + + + + hibernate.default_entity_mode + + + Set a default mode for entity representation for all sessions + opened from this SessionFactory + + dynamic-map, dom4j, + pojo + + + + + + hibernate.order_updates + + + Force 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. + + eg. + true | false + + + + + + hibernate.generate_statistics + + + If enabled, Hibernate will collect statistics useful for + performance tuning. + + eg. + true | false + + + + + + hibernate.use_identifier_rollback + + + If enabled, generated identifier properties will be + reset to default values when objects are deleted. + + eg. + true | false + + + + + + hibernate.use_sql_comments + + + If turned on, Hibernate will generate comments inside the SQL, for + easier debugging, defaults to false. + + eg. + 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. + + eg. + 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() (it is usually + safe to turn this option on). Hibernate will then use batched DML for + automatically versioned data. Defaults to false. + + eg. + true | false + + + + + + hibernate.jdbc.factory_class + + + Select a custom org.hibernate.jdbc.Batcher. Most applications + will not need this configuration property. + + eg. + 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. + + eg. + true | false + + + + + + hibernate.jdbc.use_streams_for_binary + + + Use streams when writing/reading binary or serializable + types to/from JDBC. *system-level property* + + eg. + true | false + + + + + + hibernate.jdbc.use_get_generated_keys + + + Enable 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, tries to determine the driver capabilities + using connection metadata. + + eg. + true|false + + + + + + hibernate.connection.provider_class + + + The classname of a custom org.hibernate.connection.ConnectionProvider + which provides JDBC connections to Hibernate. + + eg. + classname.of.ConnectionProvider + + + + + + hibernate.connection.isolation + + + Set 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. + + eg. + 1, 2, 4, 8 + + + + + + hibernate.connection.autocommit + + + Enables autocommit for JDBC pooled connections (not recommended). + + eg. + true | false + + + + + + hibernate.connection.release_mode + + + Specify 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, you should 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. + + eg. + auto (default) | on_close | + after_transaction | after_statement + + + Note that 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. + See + + + + + + hibernate.connection.<propertyName> + + + Pass the JDBC property <propertyName> + to DriverManager.getConnection(). + + + + + hibernate.jndi.<propertyName> + + + Pass the property <propertyName> to + the JNDI InitialContextFactory. + + + + +
+ + + Hibernate Cache Properties + + + + + + Property name + Purpose + + + + + + hibernate.cache.provider_class + + + The classname of a custom CacheProvider. + + eg. + classname.of.CacheProvider + + + + + + hibernate.cache.use_minimal_puts + + + Optimize 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. + + eg. + true|false + + + + + + hibernate.cache.use_query_cache + + + Enable the query cache, individual queries still have to be set cachable. + + eg. + true|false + + + + + + hibernate.cache.use_second_level_cache + + + May be used to completely disable the second level cache, which is enabled + by default for classes which specify a <cache> + mapping. + + eg. + true|false + + + + + + hibernate.cache.query_cache_factory + + + The classname of a custom QueryCache interface, + defaults to the built-in StandardQueryCache. + + eg. + classname.of.QueryCache + + + + + + hibernate.cache.region_prefix + + + A prefix to use for second-level cache region names. + + eg. + prefix + + + + + + hibernate.cache.use_structured_entries + + + Forces Hibernate to store data in the second-level cache + in a more human-friendly format. + + eg. + 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). + + eg. + classname.of.TransactionFactory + + + + + + jta.UserTransaction + + + A JNDI name used by JTATransactionFactory to + obtain the JTA UserTransaction from the + application server. + + eg. + jndi/composite/name + + + + + + hibernate.transaction.manager_lookup_class + + + The classname of a TransactionManagerLookup + - required when JVM-level caching is enabled or when using hilo + generator in a JTA environment. + + eg. + 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, see + . + + eg. + 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 + utomatic session context management is preferred, see + . + + eg. + true | false + + + + + +
+ + + Miscellaneous Properties + + + + + + Property name + Purpose + + + + + + hibernate.current_session_context_class + + + Supply a (custom) strategy for the scoping of the "current" + Session. See + for more + information about the built-in strategies. + + eg. + jta | thread | + managed | custom.Class + + + + + + hibernate.query.factory_class + + + Chooses the HQL parser implementation. + + eg. + org.hibernate.hql.ast.ASTQueryTranslatorFactory or + org.hibernate.hql.classic.ClassicQueryTranslatorFactory + + + + + + hibernate.query.substitutions + + + Mapping from tokens in Hibernate queries to SQL tokens + (tokens might be function or literal names, for example). + + eg. + hqlLiteral=SQL_LITERAL, hqlFunction=SQLFUNC + + + + + + hibernate.hbm2ddl.auto + + + Automatically validate or export 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. + + eg. + validate | update | + create | create-drop + + + + + + hibernate.cglib.use_reflection_optimizer + + + Enables use of CGLIB instead of runtime reflection (System-level + property). Reflection can sometimes be useful when troubleshooting, + note that Hibernate always requires CGLIB even if you turn off the + optimizer. You can not set this property in hibernate.cfg.xml. + + eg. + true | false + + + + + +
+ + + SQL Dialects + + + You should 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, saving you the effort of specifying them manually. + + + + Hibernate SQL Dialects (<literal>hibernate.dialect</literal>) + + + + + 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/10g org.hibernate.dialect.Oracle9Dialect + + + 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 + + + +
+ + + + + Outer Join Fetching + + + If your database supports ANSI, Oracle or Sybase style outer joins, outer join + fetching will often increase performance by limiting the number of round + trips to and from the database (at the cost of possibly more work performed by + the database itself). Outer join fetching allows a whole graph of objects connected + by many-to-one, one-to-many, many-to-many and one-to-one associations to be retrieved + in a single SQL SELECT. + + + + Outer join fetching may be disabled globally by setting + the property hibernate.max_fetch_depth to 0. + A setting of 1 or higher enables outer join fetching for + one-to-one and many-to-one associations which have been mapped with + fetch="join". + + + + See for more information. + + + + + + Binary Streams + + + Oracle limits the size of byte arrays that may + be passed to/from its JDBC driver. If you wish to use large instances of + binary or serializable type, you should + enable hibernate.jdbc.use_streams_for_binary. + This is a system-level setting only. + + + + + + Second-level and query cache + + + The properties prefixed by hibernate.cache + allow you to use a process or cluster scoped second-level cache system + with Hibernate. See the for + more details. + + + + + + Query Language Substitution + + + You may define new Hibernate query tokens using hibernate.query.substitutions. + For example: + + + hibernate.query.substitutions true=1, false=0 + + + would cause the tokens true and false to be translated to + integer literals in the generated SQL. + + + hibernate.query.substitutions toLowercase=LOWER + + + would allow you to rename the SQL LOWER function. + + + + + + Hibernate statistics + + + If you enable hibernate.generate_statistics, Hibernate will + expose a number of metrics that are useful when tuning a running system via + SessionFactory.getStatistics(). Hibernate can even be configured + to expose these statistics via JMX. Read the Javadoc of the interfaces in + org.hibernate.stats for more information. + + + + + + + Logging + + + Hibernate utilizes Simple Logging Facade for Java + (SLF4J) in order to log various system events. SLF4J can direct your logging output to + several logging frameworks (NOP, Simple, log4j version 1.2, JDK 1.4 logging, JCL or logback) depending on your + chosen binding. In order to setup logging properly you will need slf4j-api.jar in + your classpath together with the jar file for your preferred binding - slf4j-log4j12.jar + in the case of Log4J. See the SLF4J documentation for more detail. + To use Log4j you will also need to place a log4j.properties file in your classpath, + an example properties file is distributed with Hibernate in the src/ directory. + + + + We strongly recommend that you familiarize yourself with Hibernate's log + messages. A lot of work has been put into making the Hibernate log as + detailed as possible, without making it unreadable. It is an essential + troubleshooting device. The most interesting log categories are the + following: + + + + Hibernate Log Categories + + + + + + Category + Function + + + + + org.hibernate.SQL + Log all SQL DML statements as they are executed + + + org.hibernate.type + Log all JDBC parameters + + + org.hibernate.tool.hbm2ddl + Log all SQL DDL statements as they are executed + + + org.hibernate.pretty + + Log the state of all entities (max 20 entities) associated + with the session at flush time + + + + org.hibernate.cache + Log all second-level cache activity + + + org.hibernate.transaction + Log transaction related activity + + + org.hibernate.jdbc + Log all JDBC resource acquisition + + + org.hibernate.hql.ast.AST + + Log HQL and SQL ASTs during query parsing + + + + org.hibernate.secure + Log all JAAS authorization requests + + + org.hibernate + + Log everything (a lot of information, but very useful for + troubleshooting) + + + + +
+ + + When developing applications with Hibernate, you should almost always work with + debug enabled for the category org.hibernate.SQL, + or, alternatively, the property hibernate.show_sql enabled. + + + + + + + Implementing a <literal>NamingStrategy</literal> + + + The interface org.hibernate.cfg.NamingStrategy allows you + to specify a "naming standard" for database objects and schema elements. + + + + You may provide rules for automatically generating database identifiers from + Java identifiers or for processing "logical" column and table names given in + the mapping file into "physical" table and column names. This feature helps + reduce the verbosity of the mapping document, eliminating repetitive noise + (TBL_ prefixes, for example). The default strategy used by + Hibernate is quite minimal. + + + + You may specify a different strategy by calling + Configuration.setNamingStrategy() before adding mappings: + + + + + + org.hibernate.cfg.ImprovedNamingStrategy is a built-in + strategy that might be a useful starting point for some applications. + + + + + + XML configuration file + + + An alternative approach to configuration is to specify a full configuration in + a file named hibernate.cfg.xml. This file can be used as a + replacement for the hibernate.properties file or, if both + are present, to override properties. + + + + The XML configuration file is by default expected to be in the root o + your CLASSPATH. Here is an example: + + + + + + + + + + + + java:/comp/env/jdbc/MyDB + org.hibernate.dialect.MySQLDialect + false + + org.hibernate.transaction.JTATransactionFactory + + java:comp/UserTransaction + + + + + + + + + + + + +]]> + + + As you can see, the advantage of this approach is the externalization of the + mapping file names to configuration. The hibernate.cfg.xml + is also more convenient once you have to tune the Hibernate cache. Note that is + your choice to use either hibernate.properties or + hibernate.cfg.xml, both are equivalent, except for the above + mentioned benefits of using the XML syntax. + + + + With the XML configuration, starting Hibernate is then as simple as + + + + + + You can pick a different XML configuration file using + + + + + + + + J2EE Application Server integration + + + Hibernate has the following integration points for J2EE infrastructure: + + + + + + Container-managed datasources: Hibernate can use + JDBC connections managed by the container and provided through JNDI. Usually, + a JTA compatible TransactionManager and a + ResourceManager take care of transaction management (CMT), + esp. distributed transaction handling across several datasources. You may + of course also demarcate transaction boundaries programmatically (BMT) or + you might want to use the optional Hibernate Transaction + API for this to keep your code portable. + + + + + + + + Automatic JNDI binding: Hibernate can bind its + SessionFactory to JNDI after startup. + + + + + + + + JTA Session binding: The Hibernate Session + may be automatically bound to the scope of JTA transactions. Simply + lookup the SessionFactory from JNDI and get the current + Session. Let Hibernate take care of flushing and closing the + Session when your JTA transaction completes. Transaction + demarcation is either declarative (CMT) or programmatic (BMT/UserTransaction). + + + + + + + + JMX deployment: If you have a JMX capable application server + (e.g. JBoss AS), you can chose to deploy Hibernate as a managed MBean. This saves + you the one line startup code to build your SessionFactory from + a Configuration. The container will startup your + HibernateService, and ideally also take care of service + dependencies (Datasource has to be available before Hibernate starts, etc). + + + + + + Depending on your environment, you might have to set the configuration option + hibernate.connection.aggressive_release to true if your + application server shows "connection containment" exceptions. + + + + Transaction strategy configuration + + + The Hibernate Session API is independent of any transaction + demarcation system in your architecture. If you let Hibernate use JDBC directly, + through a connection pool, you may begin and end your transactions by calling + the JDBC API. If you run in a J2EE application server, you might want to use bean-managed + transactions and call the JTA API and UserTransaction when needed. + + + + To keep your code portable between these two (and other) environments we recommend the optional + Hibernate Transaction API, which wraps and hides the underlying system. + You have to specify a factory class for Transaction instances by setting the + Hibernate configuration property hibernate.transaction.factory_class. + + + + There are three standard (built-in) choices: + + + + + org.hibernate.transaction.JDBCTransactionFactory + + delegates to database (JDBC) transactions (default) + + + + org.hibernate.transaction.JTATransactionFactory + + + delegates to container-managed transaction if an existing transaction is + underway in this context (e.g. EJB session bean method), otherwise + a new transaction is started and bean-managed transaction are used. + + + + + org.hibernate.transaction.CMTTransactionFactory + + delegates to container-managed JTA transactions + + + + + + You may also define your own transaction strategies (for a CORBA transaction service, + for example). + + + + Some features in Hibernate (i.e. the second level cache, Contextual Sessions with JTA, etc.) + require access to the JTA TransactionManager in a managed environment. + In an application server you have to specify how Hibernate should obtain a reference to the + TransactionManager, since J2EE does not standardize a single mechanism: + + + + JTA TransactionManagers + + + + + + Transaction Factory + Application Server + + + + + org.hibernate.transaction.JBossTransactionManagerLookup + JBoss + + + org.hibernate.transaction.WeblogicTransactionManagerLookup + Weblogic + + + org.hibernate.transaction.WebSphereTransactionManagerLookup + WebSphere + + + org.hibernate.transaction.WebSphereExtendedJTATransactionLookup + WebSphere 6 + + + org.hibernate.transaction.OrionTransactionManagerLookup + Orion + + + org.hibernate.transaction.ResinTransactionManagerLookup + Resin + + + org.hibernate.transaction.JOTMTransactionManagerLookup + JOTM + + + org.hibernate.transaction.JOnASTransactionManagerLookup + JOnAS + + + org.hibernate.transaction.JRun4TransactionManagerLookup + JRun4 + + + org.hibernate.transaction.BESTransactionManagerLookup + Borland ES + + + +
+ + + + + JNDI-bound <literal>SessionFactory</literal> + + + A JNDI bound Hibernate SessionFactory can simplify the lookup + of the factory and the creation of new Sessions. Note that this + is not related to a JNDI bound Datasource, both simply use the + same registry! + + + + If you wish to have the SessionFactory bound to a JNDI namespace, specify + a name (eg. java:hibernate/SessionFactory) using the property + hibernate.session_factory_name. If this property is omitted, the + SessionFactory will not be bound to JNDI. (This is especially useful in + environments with a read-only JNDI default implementation, e.g. Tomcat.) + + + + When binding the SessionFactory to JNDI, Hibernate will use the values of + hibernate.jndi.url, hibernate.jndi.class to instantiate + an initial context. If they are not specified, the default InitialContext + will be used. + + + + Hibernate will automatically place the SessionFactory in JNDI after + you call cfg.buildSessionFactory(). This means you will at least have + this call in some startup code (or utility class) in your application, unless you use + JMX deployment with the HibernateService (discussed later). + + + + If you use a JNDI SessionFactory, an EJB or any other class may + obtain the SessionFactory using a JNDI lookup. + + + + We recommend that you bind the SessionFactory to JNDI in + a managed environment and use a static singleton otherwise. + To shield your application code from these details, we also recommend to hide the + actual lookup code for a SessionFactory in a helper class, + such as HibernateUtil.getSessionFactory(). Note that such a + class is also a convenient way to startup Hibernate—see chapter 1. + + + + + + Current Session context management with JTA + + + The easiest way to handle Sessions and transactions is + Hibernates automatic "current" Session management. + See the discussion of current sessions. + Using the "jta" session context, if there is no Hibernate + Session associated with the current JTA transaction, one will + be started and associated with that JTA transaction the first time you call + sessionFactory.getCurrentSession(). The Sessions + retrieved via getCurrentSession() in "jta" context + will be set to automatically flush before the transaction completes, close + after the transaction completes, and aggressively release JDBC connections + after each statement. This allows the Sessions to + be managed by the life cycle of the JTA transaction to which it is associated, + keeping user code clean of such management concerns. Your code can either use + JTA programmatically through UserTransaction, or (recommended + for portable code) use the Hibernate Transaction API to set + transaction boundaries. If you run in an EJB container, declarative transaction + demarcation with CMT is preferred. + + + + + + JMX deployment + + + The line cfg.buildSessionFactory() still has to be executed + somewhere to get a SessionFactory into JNDI. You can do this + either in a static initializer block (like the one in + HibernateUtil) or you deploy Hibernate as a managed + service. + + + + Hibernate is distributed with org.hibernate.jmx.HibernateService + for deployment on an application server with JMX capabilities, such as JBoss AS. + The actual deployment and configuration is vendor specific. Here is an example + jboss-service.xml for JBoss 4.0.x: + + + + + + + + + jboss.jca:service=RARDeployer + jboss.jca:service=LocalTxCM,name=HsqlDS + + + java:/hibernate/SessionFactory + + + java:HsqlDS + org.hibernate.dialect.HSQLDialect + + + + org.hibernate.transaction.JTATransactionFactory + + org.hibernate.transaction.JBossTransactionManagerLookup + true + true + + + 5 + + + true + org.hibernate.cache.EhCacheProvider + true + + + true + + + auction/Item.hbm.xml,auction/Category.hbm.xml + + + +]]> + + + This file is deployed in a directory called META-INF and packaged + in a JAR file with the extension .sar (service archive). You also need + to package Hibernate, its required third-party libraries, your compiled persistent classes, + as well as your mapping files in the same archive. Your enterprise beans (usually session + beans) may be kept in their own JAR file, but you may include this EJB JAR file in the + main service archive to get a single (hot-)deployable unit. Consult the JBoss AS + documentation for more information about JMX service and EJB deployment. + + + + + + + +