âś… What Are They?
Feature |
_inherit |
_inherits |
| Inheritance | Classical Odoo inheritance | Delegation inheritance |
| DB Structure | Works on same table (shared) | Works on multiple tables (linked) |
| Use Case | Extend behavior or add fields | Compose new models using others |
| Field Access | Direct | Delegated via foreign key |
 📌 Realistic Examples : Sales Summary by Customer
🔧 Example:
class InheritPartner(models.Model):
    _inherit = ‘res.partner’
​
    loyalty_points = fields.Integer(string=“Loyalty Points”)
​
    def custom_method(self):
        # extending existing method
        pass
âś… This will add a new field directly to the res.partner table.
đź“Ś Use Case:
Used when you want to reuse another model’s fields and data but store your own fields in a separate table.
🔧 Example:
class StudentRecord(models.Model):
_name = ‘student.record’
_inherits = {‘res.partner’: ‘partner_id’}
partner_id = fields.Many2one(‘res.partner’, required=True, ondelete=‘cascade’)
student_code = fields.Char(string=‘Student Code’)
⚠️ Key Points
Concept |
Details |
| _auto = False | Prevents Odoo from creating a DB table. |
| init()Â method | Used to manually create SQL view via raw SQL. |
| tools.drop_view_if_exists() | Utility to safely recreate views on module upgrade. |
| id field | Must be present and unique in the view for Odoo to work properly. |
âś… This allows you to:
- Store student-specific data in student.record
- Reuse all res.partner fields as if they belong to student.record
student = self.env[‘student.record’].browse(1)
print(student.name)Â # from res.partner
print(student.student_code)Â # from student.record
🎯 When to Use What?
Use Case |
Use _inherit |
Use _inherits |
| Extend existing model’s features | ✅ Yes | 🚫 No |
| Combine models like composition | đźš« No | âś… Yes |
| Need separate table and identity | đźš« No | âś… Yes |
| Add or override methods | âś… Yes | đźš« Limited |
⚙️ Internal Difference
Feature |
_inherit |
_inherits |
| Field resolution | From current model/table | Redirected to foreign model via M2O |
| Record identity | Same record ID and table | Separate IDs (joined by foreign key) |
| DB schema | Fields added directly to base model | Separate table with relationship |
âś… Summary Table
Attribute |
Purpose |
Storage |
Real Use Case |
| _inherit | Extend existing model (fields/methods) | Shared table | Add extra fields to res.partner |
| _inherits | Reuse another model with linkage | Separate table | Create student.record from partner |
🧠Developer Tips
- Use _inherit for 90% of extension work.
- Use _inherits only when modeling something structurally distinct but sharing core data.
- Avoid mixing both in the same model unless explicitly required.
- Be careful with record deletion in _inherits – always set ondelete=’cascade’ for clean joins.
