Reference Code Mixin

Author: Yousef M. Y. Al Sabbah
Version: 18.0.1.0.0
Category: Technical

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The Problem

In real Odoo projects, many models need:

• A human-readable reference (e.g., SO001, PO001, REQ001)
• Auto-generated sequence numbers
• A consistent display name format

Without a mixin, developers copy the same logic repeatedly:

# This code is repeated in EVERY model that needs a reference!
reference = fields.Char(required=True, copy=False, default='New')

@api.model_create_multi
def create(self, vals_list):
    for vals in vals_list:
        if vals.get('reference', 'New') == 'New':
            vals['reference'] = self.env['ir.sequence'].next_by_code('my.sequence')
    return super().create(vals_list)

def name_get(self):
    return [(r.id, f"[{r.reference}] {r.name}") for r in self]

This is copied across:

• Sales Orders
• Purchase Orders
• Requests, Tickets, Assets
• Custom workflows

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The Solution: A Mixin!

"This model has a reference code and knows how to display itself."

This is a CAPABILITY, not a business concept → Perfect for a Mixin!

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Usage

Step 1: Inherit the Mixin

from odoo import fields, models

class MyRequest(models.Model):
    _name = 'my.request'
    _description = 'My Request'
    _inherit = ['reference.mixin']  # <-- Just add this!
    
    # Set your sequence code
    _reference_sequence = 'my.request.sequence'
    
    # Your fields (reference is inherited!)
    name = fields.Char(string='Name')

Step 2: Create a Sequence

<record id="sequence_my_request" model="ir.sequence">
    <field name="name">My Request Sequence</field>
    <field name="code">my.request.sequence</field>
    <field name="prefix">REQ</field>
    <field name="padding">5</field>
</record>

Step 3: Done!

Your model now has:

• ✅ reference field (auto-generated)
• ✅ display_name computed as [REF00001] Name
• ✅ Sequence generation on create

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What You Get

Feature	Description
reference field	Auto-generated, readonly, indexed
display_name	Computed from reference + name
create() override	Generates sequence automatically
Company support	Works with multi-company

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Configuration Options

Override these in your model:

class MyModel(models.Model):
    _name = 'my.model'
    _inherit = ['reference.mixin']
    
    # Required: Your sequence code
    _reference_sequence = 'my.model.sequence'
    
    # Optional: Change field name (default: 'reference')
    _reference_field = 'reference'
    
    # Optional: Change default value (default: 'New')
    _reference_default = 'New'

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Real Odoo Examples

This mixin follows the same pattern used in Odoo core:

Module	Model	Sequence
Sale	sale.order	SO00001
Purchase	purchase.requisition	PR00001
Stock	stock.picking.batch	BATCH/00001

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Demo Model

This module includes a demo.request model that demonstrates the mixin in action.

After installation:

1. Go to Reference Mixin Demo menu
2. Create a new Demo Request
3. Notice the reference is auto-generated (REQ00001, REQ00002, etc.)

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File Structure

odt_reference_mixin/
├── __init__.py
├── __manifest__.py
├── README.md
├── data/
│   └── sequence_data.xml      # Demo sequence
├── models/
│   ├── __init__.py
│   ├── reference_mixin.py     # THE MIXIN
│   └── demo_request.py        # Demo model
├── security/
│   └── ir.model.access.csv
└── views/
    ├── demo_request_views.xml
    └── menu_views.xml

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License

LGPL-3

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Author: Yousef M. Y. Al Sabbah