On 2016-05-05 17:43, Sergi Almacellas Abellana wrote:
> El 05/05/16 a les 17:35, Clemens Hupka ha escrit:
> >Hello!
> >
> >I'm working on a ticket reservation and selling system based on tryton 3.8.
> >
> >As discussed with pokoli on #tryton, my model is quite special because i
> >have two one2many-relations towards ticket.ticket (one from
> >ticket.reservation and one from ticket.sale).
>
> Here is the link to the discussion on the irc:
>
> http://www.tryton.org/~irclog/2016-05-05.log.html#t2016-05-05%2015:09
> >
> >The goal was to get all tickets of a reservation into a sale with the
> >following on_change function (the number of tickets in the system should
> >be kept constant). The problem is, that with this piece of code the
> >number of reserved ticket is newly created, so if i select a reservation
> >with tickets id:162 and id:163 it creates me two new empty tickets
> >instead of updating the reserved ones...
>
> As shown in the irclog, this Returns:
>
> [{'tickets': defaultdict(, {'add': [(0, {}), (1, {})]})}]
>
> To the client code, because the records have no modified property.
> So I'm wondering if we should at least return the id in order to relate
> already existing records.
The code managed this behaviour is:
http://hg.tryton.org/trytond/file/default/trytond/model/modelview.py#l673
With the active record design, it had to choose the behaviour of the
on_change for the One2Many and the Many2Many. We could not mix both
because they have incompatible design (dict actions vs list of ids).
I think the older design was a little bit problematic because when
overriding we could be know which one will be used.
So it was decided to stick on_change behaviour to the default behaviour
of the client which means for One2Many: create, update and delete and
for ManyMany: add/remove.
> >Here is the code:
> >
> >class Ticketsale(ModelSQL, ModelView):
> > """
> >Ticket sale
> >"""
> > __name__ = 'ticket.sale'
> > receipt_number = fields.Char('Receipt number', readonly=True,
> >select=True)
> > pos_create_date = fields.DateTime('Create date', readonly=True)
> > reservation = fields.Many2One('ticket.reservation', 'Reservation')
> > voucher = fields.Many2One('ticket.voucher', 'Voucher')
> > tickets = fields.One2Many('ticket.ticket', 'sale', "Tickets")
> > @fields.depends('reservation','tickets')
> > def on_change_reservation(self):
> > if self.reservation:
> > tkts = list(self.tickets)
> > for t in self.reservation.tickets:
> > tkts.append(t)
> > self.tickets = tuple(tkts)
> >
> >I already found another solution with the use of a button. Just wanted
> >to know (btw pokoli too) if the behaviour of tryton is correct in that
> >(indeed very special and uncommon) case.
I think the behaviour of Tryton shows you that there is a design issue
in this code. The tickers should be a Many2Many even if you would like
to have ticket linked to only one sale. I said that because nothing
prevent the user to select a reservation that is already selected on
another sale so you will re-link the tickets from one sale to another.
I think it is not what you want.
If you are using a Many2Many (with a unique constraint), this case will
raise an error and so the user could correct it.
--
Cédric Krier - B2CK SPRL
Email/Jabber: cedric.kr...@b2ck.com
Tel: +32 472 54 46 59
Website: http://www.b2ck.com/
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