After generate persistence mapping from database source the "persistence.xml" was created. I had manually set
<property name="hibernate.connection.username" value="username"/>
<property name="hibernate.connection.password" value="userpassword"/>
and everything work fine. But when a new persistence mapping is generating this values are overwrote and
become empty. It's necessary to set them again. Are there any options for set these values from a
data source properties or prevent overwriting after each mapping generation?