Hello all,
I'm fairly new to hibernate, though I'm not new to ORM concepts.
I read the official h8 version 3 tutorial, as well as other articles and
examples out there.

Now the problem is that I can't figure out how the best way to map the
following tables:

table USERS (
   `userID` int(11) unsigned NOT NULL auto_increment,
   `name` varchar(255) NOT NULL,
   `lastName` varchar(255) NOT NULL,
   `nickname` varchar(20) NOT NULL,
   PRIMARY KEY  (`userID`),
   KEY `nickname`  (`nickname`)  ---> indice
)

table FRIENDS (
   `userID` int(11) unsigned NOT NULL default '0',
   `friendID` int(11) unsigned NOT NULL default '0',
   PRIMARY KEY (`userID`,`friendID`),
   KEY `friendID` (`friendID`),
   CONSTRAINT `friends_ibfk_1` FOREIGN KEY (`userID`) REFERENCES `users`
(`userID`),
   CONSTRAINT `friends_ibfk_2` FOREIGN KEY (`friendID`) REFERENCES `users`
(`userID`)
)

table MESSAGES (
   `messageID` int(11) unsigned NOT NULL auto_increment,
   `from` int(11) unsigned NOT NULL,
   `to` int(11) unsigned NOT NULL,
   `message` varchar(4000) default NULL,
   PRIMARY KEY (`messageID`),
   KEY `from` (`from`),
   KEY `to` (`to`),
   CONSTRAINT `messages_ibfk_1` FOREIGN KEY (`from`) REFERENCES `users`
(`userID`),
   CONSTRAINT `messages_ibfk_2` FOREIGN KEY (`to`) REFERENCES `users`
(`userID`)
)

I'm stuck with my implementation of the "friendship" relationship, as I
decided to define it with a directed-graph, thus user.A and user.B are
"friends" if and only if
( FRIENDS.userID = user.A ; FRIENDS.friendID = user.B ) AND  (
FRIENDS.userID = user.B ; FRIENDS.friendID = user.A )
Hence, the composite-id (userID, friendID) of FRIENDS table.

As for table MESSAGES, both FROM and TO referentiate USERS.userID (and I'm
stuck with that too )

Thanks in advance!
Matteo