In mymodel3, you will need to pass a context on the field which you are creating as a relational field to the mymain model and define a _compute_display_name method which will display the description instead of the name on the relational field.

class MyModel3(models.Model):
_name = 'my.model3'

@api.depends_context('show_desc')
def _compute_display_name(self):
    for record in self:
        desc = self.env.context.get('show_desc', False)
        name = record.description if desc and record.description else record.name
        record.display_name = name

mymain_desctiption_id = fields.Many2one('my.main', 'Description from MyMain', context={'show_desc': True})

Try this out this may work for you !

Hi, 

You can achieve this by using the related attribute in the fields definition. Here's how you can implement it for both mymodel2.py and mymodel3.py:

Assuming your mymain.py looks like this:

from odoo import models, fields

class MyMain(models.Model):
    _name = 'my.main'

    name = fields.Char(string='Name')
    description = fields.Text(string='Description')
    status = fields.Char(string='Status')

Now, for mymodel2.py:

from odoo import models, fields class MyModel2(models.Model): _name = 'my.model2' name_id = fields.Many2one('my.main', string='Name', required=True) name = fields.Char(related='name_id.name', string='Related Name', store=True)

And for mymodel3.py:

from odoo import models, fields

class MyModel3(models.Model):
    _name = 'my.model3'

    description_id = fields.Many2one('my.main', string='Description', required=True)
    description = fields.Text(related='description_id.description', string='Related Description', store=True)

Hope it helps