jboss deletes data from mysql db when it reboots

[garda86]

hello,
I have a serious problem.
I use JBoss 4.2.3 with JDK6, a database with MySQL and Eclipse to develope my application.
My problem is that whenever I restart my JBoss Server all the data in my db are deleted and in addition some charateristics of the attributes of the table are modified (for instance, all the varchar(x) become varchar(255)).
Can someone help me???
Thankyou

[peterj]

Sounds like you are using Hibernate (JPA) to handle database access and that hibernate.hbm2ddl.auto is set to create or create-drop in the persistence.xml file.