I'm building a Kohaha application to manage sip lines in asterisk.

I'm wanting to use ORM but I'm wondering how do relate certain tables that are already well established.

e.g. the table sip_lines looks like this.

+--------------------+------------------+------+-----+-------------------+-----------------------------+
| Field              | Type             | Null | Key | Default           | Extra                       |
+--------------------+------------------+------+-----+-------------------+-----------------------------+
| id                 | int(10) unsigned | NO   | PRI | NULL              | auto_increment              |
| sip_name           | varchar(80)      | NO   | UNI | NULL              |                             |
| displayname        | varchar(48)      | NO   |     | NULL              |                             |
| line_num           | varchar(10)      | NO   | MUL | NULL              |                             |
| model              | varchar(12)      | NO   | MUL | NULL              |                             |
| mac                | varchar(16)      | NO   | MUL | NULL              |                             |
| areacode           | varchar(6)       | NO   | MUL | NULL              |                             |
| per_line_astpp_acc | tinyint(1)       | NO   |     | 0                 |                             |
| play_warning       | tinyint(1)       | NO   |     | 0                 |                             |
| callout_disabled   | tinyint(1)       | NO   |     | 0                 |                             |
| notes              | varchar(80)      | NO   |     | NULL              |                             |
| last_update        | timestamp        | NO   |     | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
+--------------------+------------------+------+-----+-------------------+-----------------------------+

sip_buddies is this:

+----------------+------------------------------+------+-----+-----------+----------------+
| Field          | Type                         | Null | Key | Default   | Extra          |
+----------------+------------------------------+------+-----+-----------+----------------+
| id             | int(11)                      | NO   | PRI | NULL      | auto_increment | 
| name           | varchar(80)                  | NO   | UNI |           |                | 
| host           | varchar(31)                  | NO   |     |           |                | |                |
| lastms         | int(11)                      | NO   |     | 0         
*** snip ***
+----------------+------------------------------+------+-----+-----------+----------------+

The two tables are actually related as sip_lines.sip_name = sip_buddies.name

How do I relate them in Kohana ORM as this wouldn't be quite right would it?

<?php defined('SYSPATH') or die('No direct script access.');

/* A model for all the account information */
class Sip_Line_Model extends ORM
{
    protected $has_one = array("sip_buddies");
}

?>

EDIT: Actually, it'd be fair to say that these tables are not properly related with foreign keys! doh.

EDIT: Looks like Kohana ORM is not that flexible. ORM is probably not the way to go and works best for completely new projects where the data model can be altered. The reason being that the key names must follow a specific naming convention or else they won't relate in Kohana.