Appendix A. Configuration properties

Many configuration settings define pluggable strategies that Hibernate uses for various purposes. The configuration of many of these strategy type settings accept definition in various forms. The documentation of such configuration settings refer here. The types of forms available in such cases include:

short name (if defined): Certain built-in strategy implementations have a corresponding short name.
strategy instance: An instance of the strategy implementation to use can be specified
strategy Class reference: A java.lang.Class reference of the strategy implementation to use can be specified
strategy Class name: The class name (java.lang.String) of the strategy implementation to use can be specified

A.2. General Configuration

hibernate.dialect	A fully-qualified classname	The classname of a Hibernate `org.hibernate.dialect.Dialect` from which Hibernate can generate SQL optimized for a particular relational database. In most cases Hibernate can choose the correct `org.hibernate.dialect.Dialect` implementation based on the JDBC metadata returned by the JDBC driver.
hibernate.show_sql	`true` or `false`	Write all SQL statements to the console. This is an alternative to setting the log category org.hibernate.SQL to debug.
hibernate.format_sql	`true` or `false`	Pretty-print the SQL in the log and console.
hibernate.default_schema	A schema name	Qualify unqualified table names with the given schema or tablespace in generated SQL.
hibernate.default_catalog	A catalog name	Qualifies unqualified table names with the given catalog in generated SQL.
hibernate.session_factory_name	A JNDI name	The `org.hibernate.SessionFactory` is automatically bound to this name in JNDI after it is created.
hibernate.max_fetch_depth	A value between `0` and `3`	Sets a maximum depth for the outer join fetch tree for single-ended associations. A single-ended assocation is a one-to-one or many-to-one assocation. A value of `0` disables default outer join fetching.
hibernate.default_batch_fetch_size	`4`,`8`, or `16`	Default size for Hibernate batch fetching of associations.
hibernate.default_entity_mode	`dynamic-map` or `pojo`	Default mode for entity representation for all sessions opened from this `SessionFactory`, defaults to `pojo`.
hibernate.order_updates	`true` or `false`	Forces Hibernate to order SQL updates by the primary key value of the items being updated. This reduces the likelihood of transaction deadlocks in highly-concurrent systems.
hibernate.order_by.default_null_ordering	`none`, `first` or `last`	Defines precedence of null values in `ORDER BY` clause. Defaults to `none` which varies between RDBMS implementation.
hibernate.generate_statistics	`true` or `false`	Causes Hibernate to collect statistics for performance tuning.
hibernate.use_identifier_rollback	`true` or `false`	If true, generated identifier properties are reset to default values when objects are deleted.
hibernate.use_sql_comments	`true` or `false`	If true, Hibernate generates comments inside the SQL, for easier debugging.

A.3. Database configuration

Table A.1. JDBC properties

Property	Example	Purpose
hibernate.jdbc.fetch_size	`0` or an integer	A non-zero value determines the JDBC fetch size, by calling `Statement.setFetchSize()`.
hibernate.jdbc.batch_size	A value between `5` and `30`	A non-zero value causes Hibernate to use JDBC2 batch updates.
hibernate.jdbc.batch_versioned_data	`true` or `false`	Set this property to `true` if your JDBC driver returns correct row counts from `executeBatch()`. This option is usually safe, but is disabled by default. If enabled, Hibernate uses batched DML for automatically versioned data.
hibernate.jdbc.factory_class	The fully-qualified class name of the factory	Select a custom `org.hibernate.jdbc.Batcher`. Irrelevant for most applications.
hibernate.jdbc.use_scrollable_resultset	`true` or `false`	Enables Hibernate to use JDBC2 scrollable resultsets. This property is only relevant for user-supplied JDBC connections. Otherwise, Hibernate uses connection metadata.
hibernate.jdbc.use_streams_for_binary	`true` or `false`	Use streams when writing or reading binary or serializable types to or from JDBC. This is a system-level property.
hibernate.jdbc.use_get_generated_keys	`true` or `false`	Allows Hibernate to use JDBC3 `PreparedStatement.getGeneratedKeys()` to retrieve natively-generated keys after insert. You need the JDBC3+ driver and JRE1.4+. Disable this property if your driver has problems with the Hibernate identifier generators. By default, it tries to detect the driver capabilities from connection metadata.

Table A.2. Cache Properties

Property	Example	Purpose
hibernate.cache.provider_class	Fully-qualified classname	The classname of a custom CacheProvider.
hibernate.cache.use_minimal_puts	`true` or `false`	Optimizes second-level cache operation to minimize writes, at the cost of more frequent reads. This is most useful for clustered caches and is enabled by default for clustered cache implementations.
hibernate.cache.use_query_cache	`true` or `false`	Enables the query cache. You still need to set individual queries to be cachable.
hibernate.cache.use_second_level_cache	`true` or `false`	Completely disable the second level cache, which is enabled by default for classes which specify a <cache> mapping.
hibernate.cache.query_cache_factory	Fully-qualified classname	A custom `QueryCache` interface. The default is the built-in `StandardQueryCache`.
hibernate.cache.region_prefix	A string	A prefix for second-level cache region names.
hibernate.cache.use_structured_entries	`true` or `false`	Forces Hibernate to store data in the second-level cache in a more human-readable format.
hibernate.cache.auto_evict_collection_cache	`true` or `false` (default: false)	Enables the automatic eviction of a bi-directional association's collection cache when an element in the ManyToOne collection is added/updated/removed without properly managing the change on the OneToMany side.
hibernate.cache.use_reference_entries	`true` or `false`	Optimizes second-level cache operation to store immutable entities (aka "reference") which do not have associations into cache directly, this case, lots of disasseble and deep copy operations can be avoid. Default value of this property is `false`.

Table A.3. Transactions properties

Property	Example	Purpose
hibernate.transaction.factory_class	jdbc or	Names the `org.hibernate.engine.transaction.spi.TransactionFactory` strategy implementation to use. See Section A.1, “Strategy configurations” and Section 7.5.16, “`org.hibernate.engine.transaction.spi.TransactionFactory`”
jta.UserTransaction	A JNDI name	The `JTATransactionFactory` needs a JNDI name to obtain the JTA UserTransaction from the application server.
hibernate.transaction.manager_lookup_class	A fully-qualified classname	The classname of a `TransactionManagerLookup`, which is used in conjunction with JVM-level or the hilo generator in a JTA environment.
hibernate.transaction.flush_before_completion	`true` or `false`	Causes the session be flushed during the before completion phase of the transaction. If possible, use built-in and automatic session context management instead.
hibernate.transaction.auto_close_session	`true` or `false`	Causes the session to be closed during the after completion phase of the transaction. If possible, use built-in and automatic session context management instead.

Note

Each of the properties in the following table are prefixed by hibernate.. It has been removed in the table to conserve space.

Table A.4. Miscellaneous properties

Property	Example	Purpose
current_session_context_class	One of `jta`, `thread`, `managed`, or `custom.Class`	Supply a custom strategy for the scoping of the `Current` Session.
factory_class	`org.hibernate.hql.internal.ast.ASTQueryTranslatorFactory` or `org.hibernate.hql.internal.classic.ClassicQueryTranslatorFactory`	Chooses the HQL parser implementation.
query.substitutions	`hqlLiteral=SQL_LITERAL` or `hqlFunction=SQLFUNC`	Map from tokens in Hibernate queries to SQL tokens, such as function or literal names.
hbm2ddl.auto	`validate`, `update`, `create`, `create-drop`	Validates or exports schema DDL to the database when the `SessionFactory` is created. With create-drop, the database schema is dropped when the `SessionFactory` is closed explicitly.

A.4. Connection pool properties

c3p0 connection pool properties

hibernate.c3p0.min_size
hibernate.c3p0.max_size
hibernate.c3p0.timeout
hibernate.c3p0.max_statements

Table A.5. Proxool connection pool properties

Property	Description
hibernate.proxool.xml	Configure Proxool provider using an XML file (.xml is appended automatically)
hibernate.proxool.properties	Configure the Proxool provider using a properties file (.properties is appended automatically)
hibernate.proxool.existing_pool	Whether to configure the Proxool provider from an existing pool
hibernate.proxool.pool_alias	Proxool pool alias to use. Required.

Note

For information on specific configuration of Proxool, refer to the Proxool documentation available from http://proxool.sourceforge.net/.