A Complete Guide to Transient Models (Wizards) in Odoo 19

Introduction

In Odoo development, there are many scenarios  where user input is needed only for a short time. This input is processed for tasks such as validating actions, applying discounts, importing records, checking privacy details, or sending emails, and then it is no longer required. Since this data does not need to be stored permanently in the database, Odoo provides a special solution called Transient Models.

Transient models are designed to handle temporary data. They are lighter and faster compared to regular models, and Odoo automatically removes their records after a certain period. Because of this behavior, transient models are commonly used in wizard forms and for short-term user interactions.

What is a Transient Model
A Transient Model is a temporary data model used by Odoo to store short-lived information. These models are most often used in wizard forms, which appear as pop-up windows where users enter data that triggers specific actions.

Main Features of Transient Models

1. Temporary Data Storage
   Transient models are used to store data only for a short period. The records are not meant to be permanent and are automatically removed by Odoo after some time.
   
   

2. Automatic Cleanup
   Odoo automatically deletes records created in transient models, so developers do not need to manage data cleanup manually.
   
   

3. Used in Wizard Forms
   Transient models are commonly used in wizard forms (pop-up windows) where users enter information to perform specific actions.
   
   

4. Lightweight and Fast
   Compared to regular models, transient models are lightweight, making them faster and more efficient for short-term operations.
   
   

5. No Long-Term Database Impact
   Since the data is temporary, transient models do not clutter the database with unnecessary records.
   
   

6. Action-Oriented
   The main purpose of a transient model is to collect input and trigger actions such as validations, updates, imports, or email sending.

Implementation

Step 1: Define the Transient Model

Create a new Python file named rejection_wizard.py inside the wizard folder of your module.

from odoo import api, fields, models, _

class EmployeeRejectionWizard(models.TransientModel):

   _name = 'employee.rejection.wizard'

   _description = 'Employee Rejection'

   rejection_reason = fields.Char(string="Rejection Reason")

   employee_id = fields.Many2one('hr.employee')

   def button_confirm_reject(self):

       """Rejection maill will send."""

       email_values = {'user': self.employee_id.create_uid.login, 'name': self.employee_id.create_uid.name,'reason':self.rejection_reason}

       self.env.ref('zb_employee_approval.reject_mail_template').with_context(

           order=email_values).send_mail(self.employee_id.id, force_send=True)

       self.employee_id.write({'state':'reject',})

Step 2: Add Access Right for Model

access_employee_rejection_wizard,employee_rejection_wizard,model_employee_rejection_wizard,base.group_user,1,1,1,1

Step 3: Create a Form View

Create a new XML file, e.g., rejection_wizard.xml.

<?xml version="1.0" encoding="utf-8"?>

<odoo>

   <data>

       <record id="employee_rejection_wizard_form_view" model="ir.ui.view">

           <field name="name">employee.rejection.reason.wizard</field>

           <field name="model">employee.rejection.wizard</field>

           <field name="arch" type="xml">

           <!-- Rejection wizard -->

               <form>

                   <group>

                       <field name="rejection_reason" required="1"/>

                       <field name="employee_id" invisible="1"/>

                   </group>

                   <footer>

                       <button string="Confirm" name="button_confirm_reject" type="object" class="oe_highlight" data-hotkey="q"/>

                       <button string="Cancel" class="btn btn-secondary" special="cancel" data-hotkey="z"/>

                   </footer>

               </form>

           </field>

       </record>

   </data>

</odoo>

Step 4: Add an Action 

This action opens the rejection wizard in a popup window and passes the selected employee record to capture the rejection reason.

   def action_rejection(self):

       """Rejection mail will send to record created user. Capturing the reason also"""

       rejection_form = self.env.ref('zb_employee_approval.employee_rejection_wizard_form_view')

       return {

           'name': _('Employee Rejection Reason'),

           'res_model': 'employee.rejection.wizard',

           'view_mode': 'form',

           'views': [(rejection_form.id, 'form')],

           'view_id': rejection_form.id,

           'context': {

               'active_model': 'hr.employee',

               'active_ids': self.ids,

               'default_employee_id': self.id,

           },

           'target': 'new',

           'type': 'ir.actions.act_window',

       }

How Odoo Automatically Deletes Wizard Records

Odoo handles the cleanup of wizard records using its internal method:

@api.autovacuum

def _transient_vacuum(self):

The @api.autovacuum decorator marks methods to be executed automatically by Odoo’s autovacuum system.

In transient models, the _transient_vacuum() method is responsible for deleting outdated or temporary wizard records.

Developers don’t need to manually remove these records — Odoo performs this cleanup automatically, keeping the database clean and ensuring optimal performance.

Conclusion

Transient models in Odoo are designed to store temporary data during user interactions. They do not require long-term storage and are commonly used to display information through wizards. By handling short-lived data efficiently, transient models allow developers to build smooth and effective workflows without worrying about manual data cleanup, as Odoo’s autovacuum system automatically removes these records. Understanding transient models helps developers create lightweight, user-friendly, and easy-to-maintain features that enhance the overall Odoo experience.

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