How to create a One2one relationship in Odoo 8?

Question

I have two sets of data that exhibit a one-to-one relationship.

I am not able to merge the two sets of data because:

1. Particular records may be present only in set A, only in set B, or both in set A and in set B; and
2. The association between records in set A and in set B is transient, meaning records can become associated and can become disassociated; and
3. The data in set A are processed differently than the data in set B; and
4. There are external architectural constraints.

When a record in set A is associated with a record in set B, I want to link the two records. When records are linked, the relationship must be one-to-one. How do I guarantee that the relationship is a one-to-one relationship?

The following code seems close, but I am new to working with Odoo and am uncertain how to analyze whether or not this approach guarantees a one-to-one relationship.

import openerp

class A(openerp.models.Model):

  _name = 'set.a'

  _sql_constraints = [
    ('set_b_id', 'unique("set_b_id")', 'Field set_b_id must be unique.'),
  ]

  # Constrained to be unique (see SQL above) which essentially changes
  # this end of the Many2one relationship to a One2one relationship. (The
  # other end of the relationship must also be constrained.)

  set_b_id = openerp.fields.Many2one(
    comodel_name='set.b',
  )

class B(openerp.models.Model):

  _name = 'set.b'

  # Constrained to tie with either zero keys or one key (see function
  # below) which essentially changes this end of the One2many
  # relationship to a One2one relationship. (The other end of the
  # relationship must also be constrained.)

  set_a_id = openerp.fields.One2many(
    comodel_name='set.a',
    inverse_name='set_b_id',
  )

  @openerp.api.constrains('set_a_id')
  def _constrains_set_a_id(self):
    if len(self.set_a_id) > 1:
        raise openerp.exceptions.ValidationError('Additional linkage failed.')

Another approach might be to extend openerp.fields to recreate the previously deprecated One2one relationship, but I am not certain that could be done cleanly.

Answer 1

In your case basically the one-to-one relation is not available in Odoo 8.0 its totally deprecated one 7.0 or later version in Odoo (formally OpenERP).

so please my advice is that not to use one-to-one relation just use it as many2one instead and make to set your local as per your need.

I hope my answer may helpful for you :)