# 5.7\. 辅助数据库对象(Auxiliary Database Objects) Allows CREATE and DROP of arbitrary database objects, in conjunction with Hibernate's schema evolution tools, to provide 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, really any SQL command that can be run via a `java.sql.Statement.execute()` method is valid here (ALTERs, INSERTS, etc). There are essentially two modes for defining auxiliary database objects... 帮助CREATE和DROP任意数据库对象，与Hibernate的schema交互工具组合起来，可以提供在Hibernate映射文件中完全定义用户schema的能力。虽然这是为创建和销毁trigger(触发器）或stored procedure(存储过程）等特别设计的，实际上任何可以在`java.sql.Statement.execute()`方法中执行的SQL命令都可以在此使用（比如ALTER, INSERT，等等）。本质上有两种模式来定义辅助数据库对象... 第一种模式是在映射文件中显式声明CREATE和DROP命令： ``` <hibernate-mapping> ... <database-object> <create>CREATE TRIGGER my_trigger ...</create> <drop>DROP TRIGGER my_trigger</drop> </database-object> </hibernate-mapping> ``` 第二种模式是提供一个类，这个类知道如何组织CREATE和DROP命令。这个特别类必须实现`org.hibernate.mapping.AuxiliaryDatabaseObject`接口。 ``` <hibernate-mapping> ... <database-object> <definition class="MyTriggerDefinition"/> </database-object> </hibernate-mapping> ``` 还有，这些数据库对象可以特别指定为仅在特定的方言中才使用。 ``` <hibernate-mapping> ... <database-object> <definition class="MyTriggerDefinition"/> <dialect-scope name="org.hibernate.dialect.Oracle9Dialect"/> <dialect-scope name="org.hibernate.dialect.OracleDialect"/> </database-object> </hibernate-mapping> ```