from openerp import models, api, fields

from openerp.tools import ustr

class ProductProduct(models.Model):

    _inherit = "product.product"

    brand = fields.Char('brand')

    model = fields.Char('model')

    size = fields.Char('size')

    prod_name = fields.Char(compute="_get_prod_name", string="Product Name")

    @api.one

    @api.depends("brand", "model", "size")

    def _get_prod_name(self):

        brand = self.brand or ''

        model = self.model or ''

        size = self.model or ''

        name = ustr(brand) + " " + ustr(model) + " " + ustr(size)

        self.product_tmpl_id.name = name

        self.prod_name = name

Guys, I can't make it work, I already have brand, model and size declared. Why whilst am trying install new module it tells me brand not declared, etc.  After that i've had a message regarding indentation, now i have: " can only concatenate tuple (not "str") to tuple"

@Emipro,@Cyril How would you do the equivalent solution for a Saas user who only have the developper mode.

For instance I can't create a new field with a type function, because this type is not proposed under the Saas environment.

Although I really need this capacity to combine fields to name the product with the name of its composer and opus title (music domain)!

@Robert

For this, you can create a new field as of type "Function" i.e fields.function()

from openerp import models,api,fields

class product(models.Model):

    _inherit = "product.product"

    @api.one

    @api.depends("brand","model","size")

    def get_prod_name(self):

        for product in self:

            brand = product.brand_id.name or ''

            model = product.model_id.name or ''

            size = str(product.size)

            product.prod_name= brand + "_"+model+"_"+size

   prod_name = fields.Char(compute="get_prod_name", string="Product Name",store=True)

Here you declared a new field "prod_name" which is a compute field. One more thing, product.product model has a field "name_template" which generally stores the same value as the field "name" from product.template. So you need to decide here whether to take the new field "prod_name" or not. Here I treat brand_id, model_id as many2one fields.

Hope this helps !!.