如何使用休眠Pojo文件重新创建数据库

Question

I lost my projects' database from my pc. But I have my JSP project which includes hibernate. Whenever I run the project it says ' org.hibernate.exception.SQLGrammarException: Cannot open connection ' because the database not exist in the server. Can I recreate my database with the help of the POJO files? I am using netbeans and MySQL server 5.1

Answer 1

Yes you can recreate your database using hibernate. In our session factory you need to set the following property.

 <property name="jpaProperties">
   <props>
     <prop key="hibernate.hbm2ddl.auto">create</prop>
   </props>
 </property>

hibernate.hbm2ddl.auto Automatically validate or exports schema DDL to the database when the SessionFactory is created

There are a couple of caveats you need to understand:

1. This will only recreate objects which you had mapped. This process will not recreate any database object which you may have had but didn't have mapped.
2. Certain object names may not be named what they were previously. One classic example would be the names of your foreign-key constraints.

This will at least get you back up with a majority of what you lost at the very least.