Welcome back! So far, we have been building regular models using models.Model. Every time a user types data into those models and clicks save, that data lives in the PostgreSQL database forever.

But what if you don't want the data to live forever?

Imagine a user wants to print a specific report between two dates, or they want to select 50 books and apply a 20% discount to all of them at once. They need a pop-up window to enter this temporary information. Once they click "Confirm," the system does the math, and the temporary data should disappear.

In Odoo, we build these temporary pop-up windows using Wizards and Transient Models.

1. What is a Transient Model?

A Transient Model is built exactly like a regular model, but it inherits from models.TransientModel instead of models.Model.

When you use a Transient Model, Odoo still creates a table in PostgreSQL. However, Odoo has a background garbage-collection job that automatically deletes old records from this table every day. It keeps your database clean and prevents it from filling up with useless pop-up window data.

2. Creating the Wizard Model (Python)

Let's build a Wizard for our Library module. We want a pop-up window that asks the user for a "New Price", and when they click "Apply," it updates the prices of all the books they had selected in the list view.

Create a new Python file (e.g., wizard/update_price_wizard.py):

from odoo import models, fields, api

class UpdatePriceWizard(models.TransientModel):
    # Notice we use TransientModel here!
    _name = 'library.update.price.wizard'
    _description = 'Mass Update Book Prices'

    new_price = fields.Float(string='New Price', required=True)

    def action_apply_price(self):
        # 1. Get the IDs of the books the user selected before opening the wizard
        active_ids = self.env.context.get('active_ids', [])
                # 2. Fetch those specific books from the database
        books = self.env['library.book'].browse(active_ids)
                # 3. Update their prices
        for book in books:
            book.write({'price': self.new_price})
                    # 4. Tell the pop-up window to close automatically
        return {'type': 'ir.actions.act_window_close'}

3. Creating the Wizard Form (XML)

Now we need to build the user interface for our pop-up. Wizard views look just like normal form views, but they have a special <footer> section at the bottom for the buttons.

<odoo>
    <record id="view_update_price_wizard_form" model="ir.ui.view">
        <field name="name">library.update.price.wizard.form</field>
        <field name="model">library.update.price.wizard</field>
        <field name="arch" type="xml">
            <form string="Update Prices">
                <sheet>
                    <group>
                        <field name="new_price" widget="monetary"/>
                    </group>
                </sheet>
                <footer>
                    <button name="action_apply_price" string="Apply Price" type="object" class="btn-primary"/>
                    <button string="Cancel" class="btn-secondary" special="cancel"/>
                </footer>
            </form>
        </field>
    </record>
</odoo>

4. Launching the Wizard (The Action)

How do we actually open this pop-up? We create a Window Action, just like we do for regular menu items. But we add a magic ingredient: target="new".

<record id="action_update_price_wizard" model="ir.actions.act_window">
    <field name="name">Update Book Prices</field>
    <field name="res_model">library.update.price.wizard</field>
    <field name="view_mode">form</field>
    <field name="target">new</field>
    <field name="binding_model_id" ref="model_library_book"/>
    <field name="binding_view_types">list</field>
</record>

(By adding binding_model_id, Odoo automatically adds this wizard to the "Action" dropdown menu at the top of the Library Book list view!)

5. Pro-Tips & Advice

💡 PRO TIP: Don't Forget Security! Just because a model is temporary doesn't mean it bypasses security. You must add your library.update.price.wizard to your ir.model.access.csv file, exactly like you would for a normal model. If you don't, users will get an Access Error when they try to open the pop-up.

• The Power of the Context: In the Python code above, we used self.env.context.get('active_ids'). The context is a temporary dictionary that Odoo passes around the screen. When a user checks the boxes next to 5 books in a list view and clicks an Action, Odoo secretly packs the IDs of those 5 books into the context under the key active_ids. This is how wizards know what records they are supposed to act upon!

• Default Values in Wizards: You can use the default_get method to pre-fill the wizard's fields before the screen even loads. For example, you could calculate the average price of the selected books and put it in the new_price field automatically.