Hi,

api.model

The model decorator is used with the methods where self is a record set, but only the model is relevant and not its contents. It helps in the code migration since it will convert the old API calls to the new ones, which makes the migration process faster.

Here is an example code for @api.model:

@api.model
def _get_default_currency(self):
   ''' Get the default currency from either the journal, either the default journal's company. '''
   journal = self._get_default_journal()
   return journal.currency_id or journal.company_id.currency_id

api.depends

The depends decorator is used to specify the compute dependencies for a computing method. Each argument must be a string of field names, where it can be a simple or a dot-separated sequence of field names. It is possible to pass a single function as an argument, where the dependencies are given by calling the function with the field’s model.

Here is an example code for @api.depends:

complete_name = fields.Char('Complete Name', compute='_compute_complete_name', store=True)

@api.depends('name', 'parent_id.complete_name')
def _compute_complete_name(self):
   for department in self:
if department.parent_id:
   department.complete_name = '%s / %s' % (
   department.parent_id.complete_name, department.name)
else:
   department.complete_name = department.name

api.onchange

The onchange method decorator is mostly used with the onchange method for the given fields. The onchange method will be triggered while we change the value of any of the fields specified with the onchange decorator from the form view. The onchange method will be invoked on a pseudo-record that contains all the values of fields present in the form view. Even though we cannot perform the CRUD operations in that record, the field assignments are updated in the form view. The onchange decorator does not support the dotted names(fields of relational fields like product_id.default_code), and those will be ignored. We can only use simple field names.

Here is an example code for @api.onchange:

@api.onchange('analytic_account_id', 'analytic_tag_ids')
def _onchange_mark_recompute_taxes_analytic(self):
   ''' Trigger tax recomputation only when some taxes with analytics
   '''
   for line in self:
if not line.tax_repartition_line_id and any(tax.analytic for tax in line.tax_ids):
   line.recompute_tax_line = True

Regards