5.7. Auxiliary database objects
Auxiliary database objects allow for the CREATE and DROP of arbitrary database objects. In conjunction with Hibernate's schema evolution tools, they have the ability to fully define a user schema within the Hibernate mapping files. Although designed specifically for creating and dropping things like triggers or stored procedures, any SQL command that can be run via a
java.sql.Statement.execute()
method is valid (for example, ALTERs, INSERTS, etc.). There are essentially two modes for defining auxiliary database objects:
The first mode is to explicitly list the CREATE and DROP commands in the mapping file:
<hibernate-mapping> ... <database-object> <create>CREATE TRIGGER my_trigger ...</create> <drop>DROP TRIGGER my_trigger</drop> </database-object> </hibernate-mapping>
The second mode is to supply a custom class that constructs the CREATE and DROP commands. This custom class must implement the
org.hibernate.mapping.AuxiliaryDatabaseObject
interface.
<hibernate-mapping> ... <database-object> <definition class="MyTriggerDefinition"/> </database-object> </hibernate-mapping>
Additionally, these database objects can be optionally scoped so that they only apply when certain dialects are used.
<hibernate-mapping> ... <database-object> <definition class="MyTriggerDefinition"/> <dialect-scope name="org.hibernate.dialect.Oracle9iDialect"/> <dialect-scope name="org.hibernate.dialect.Oracle10gDialect"/> </database-object> </hibernate-mapping>