i have tow classes class customer_in and class customer_out
class cust_in(osv.osv)
_name = 'customer_in'
_columns = {

'name': fields.many2one('res.partner', 'Customer',domain="[('customer','=','True')]",requried=True),
'in_out': fields.one2many('customer_out','inst_id', 'Customer')
}

cust_in()
class cust_out(osv.osv)
_name = customer_out
_columns = {
'inst_id':fields.many2one('customer_in','item',readonly=True,hidden=True),
'or_no': fields.char('Order No',required=True,size=20),
}
cust_out()

Question: if i select customer from res.partner , class customer_in from field "name" this will onchange the field or_no of class customer_out
is it possible that selct a name from class customer_in and it will automatic chage the another class (customer_out) field or_no which is orderNo customer?

ponka mera n|m

use inheritence