Ok I finally found out even if I'm not sure what has really made the difference afetr the multiple reinstallations and successive configurations. Here is the mysql-ds.xml that I put in the deploy folder (I let the hsql-ds.xml) <datasources> | <local-tx-datasource> | <jndi-name>cuoreds</jndi-name> <connection-url>jdbc:mysql://localhost:3306/cuore?jdbcCompliantTruncation=false</connection-url> | <driver-class>com.mysql.jdbc.Driver</driver-class> | <user-name>root</user-name> | <password>123456</password> <exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLExceptionSorter</exception-sorter-class-name> | <metadata> | <type-mapping>mySQL</type-mapping> | </metadata> | </local-tx-datasource> | </datasources> I also add the mysql-connector-version-bn.jar file in the lib folder. And that's it. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4155889#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...