Odoo - How to add “code” field to Accounting Model

问题

I am working on a module that will print some values related to the invoice. The only two things that are missing in the Accounting Model are fields:

-vat

-code (Country Code)

I have successfully added vat field. However, get an error when trying to bring the "code" field. My py code is as follows:

from openerp import models, fields

class CountryCodeInvoice(models.Model):
# where to place new fields
    _inherit = 'account.invoice'

# getting country code to the accounting model
    code = fields.Char(string='Country Code', related='res_country.code')

class AccountInvoiceInherited(models.Model):
# where to place new fields
    _inherit = 'account.invoice'
# getting the vat field to accounting model
    vat = fields.Char(string='vat', related='partner_id.vat')

I have definitely messed up this part:

related='res_country.code'

This is the final result I am trying to get:

Do you know any tutorials that explain how to work with related fields? Official documentation does not go very deep...

回答1:

Related fields base on a relation on the model you're working on. Usually these fields are Many2one fields. You already used one for vat: partner_id which is a Many2one relation to model res.partner. You can relate to other fields of this relation, like in your example the vat of the invoice partner. You have to use dot-notation like in the most object oriented languages. But the chain doesn't stop on the first piece. So you can relate on much "deeper" relations. For example your country code:

code = fields.Char(string='Country Code', related='partner_id.country_id.code')

Again it's partner_id the chain begins with. But the country code lays deeper in the relation chain. res.partner has a Many2one relation to model res.country which holds the code. Just use dot-notation to get to it.

来源：https://stackoverflow.com/questions/50911599/odoo-how-to-add-code-field-to-accounting-model