Development Book V17: Related fields

In practical business scenarios, there are instances where we need to display the value of a field from a related model in the current model. In such cases, related fields come into play, and to implement this, we use the "related" attribute.

For example, consider a Many2one field named partner_id with a corresponding model (comodel) of res.partners. In this scenario, a related field named partner_name can be specified to display relevant information.

partner_id = fields.Many2one('res.partners')
partner_name = fields.Char('Name', related="partner_id.name")

By default, the related fields are not stored in the database, and also it is read-only and not copied fields. If we want to store the field record in the database, we can use store = True attributes.

partner_name = fields.Char('Name', related="partner_id.name", store=True)

Reference Fields

In Odoo, reference fields provide a flexible way to create dynamic relationships between models. Unlike standard relational models, where related comodels are predefined, reference fields allow users to choose both the related model and a specific record from a selection list. Users first select the target model and then pick the desired record within that model. For example, a field named "reference" could be used to select Purchase Orders, Sale Orders, or Manufacturing Orders, providing a versatile approach to establishing connections between different models.

reference_field = fields.Reference(selection='', string='Field name')

For this, we use the selection parameter. We must assign the model and its name to this parameter.

For example:

reference = fields.Reference(selection="[('sale.order', 'Sale Order'), ('purchase.order', ' Purchase Order')]", string="Reference")

Here, we can choose a Sale Order or Purchase Order, from the same field. Also possible to selection from a function.

reference = fields.Reference(selection="get_model")


@api.model
def get_model(self):
    models = self.env['ir.model'].search([])
    return [(model.model, model.name)for model in models]

Returned values must be a list.