Computed Fields Explained

What Is a Computed Field?

A computed field is a field whose value is calculated automatically based on other fields. Think of it like an Excel formula: Total = Qty * Price. When you change the source fields, the computed field updates automatically!

Common Computed Fields You Use Every Day

Field	Model	How It's Calculated
amount_total	sale.order	Sum of all order lines + taxes
price_subtotal	sale.order.line	quantity × unit price (with discounts)
display_name	res.partner	Combines name + company info
age	hr.employee	Today's date - birthday
qty_available	product.product	Sum of all stock quantities
delivery_status	sale.order	Checks if all shipments are done
amount_due	account.move	Total - Amount Paid

The Five Configurations of Computed Fields

Configuration	Stored?	Editable?	Can Filter/Group?	When to Use
Computed, Not Stored	No	No	No	Dynamic values (age, days remaining)
Computed, Stored	Yes	No	Yes	Calculated values for reporting (totals)
Computed, Stored, Editable	Yes	Yes (overwrite)	Yes	Default value user can override
Computed with Inverse	Optional	Yes (bidirectional)	If stored	Two-way binding
Computed with Precompute	Yes	Optional	Yes	Compute BEFORE record creation (Odoo 16+)

Key Behaviors to Remember

• Default store: Computed fields are store=False by default
• Default readonly: Computed fields are readonly UNLESS they have an inverse
• Default copy: Computed fields are NOT copied on duplicate, unless stored AND not readonly
• Precompute: Only works on stored fields - computes value BEFORE record creation (faster)
• @api.depends: Required for stored computed fields to know when to recalculate

Real Examples in Odoo

Where	Field	Configuration	Why?
Sales Order	Pricelist	Computed, Stored, Editable, Precompute	Default from customer, user can change
Sales Order	Currency	Computed, Stored, Editable, Precompute	Default from pricelist, editable
Event Track	Track Date	Computed, Inverse, Stored	Edit track date → updates event timing
Link Tracker	Short URL Code	Computed, Inverse, Editable	Auto-generated code, but customizable

The @api.depends Decorator - What Triggers Recalculation?

For stored computed fields, @api.depends tells Odoo when to recalculate:

@api.depends('price_unit', 'quantity')
def _compute_subtotal(self):
    for line in self:
        line.price_subtotal = line.quantity * line.price_unit

Dependency Syntax	Meaning
@api.depends('price_unit', 'quantity')	Recalculate when price or quantity changes
@api.depends('order_line.price_subtotal')	Recalculate when any order line subtotal changes
@api.depends('partner_id.country_id')	Recalculate when the customer's country changes

The Dependency Trap

If a field is used in the calculation but missing from @api.depends, the result won't update automatically!

Example:

• @api.depends('partner_id.country_id') watches partner_id and country_id
• ✓ Change the customer → Field updates
• ✓ Change the customer's country → Field updates
• ✗ Change the customer's city → Field does NOT update (city isn't watched)

Context-Dependent Fields - Same Product, Different Values

Some computed fields show different values depending on context:

The "Quantity Available" Mystery

Location	"Laptop" qty_available
Warehouse A	50 units
Warehouse B	30 units
Product form (total)	80 units

This is because qty_available is a context-dependent computed field!

How Context Works

When you open a product from different places, Odoo passes different context:

• From Warehouse A screen → {'warehouse': 'WH-A'}
• From Company X → {'company': 'Company X'}
• From a specific date report → {'date': '2024-01-15'}

The computed field uses this context to show the relevant value.

Context-Dependent Fields Cannot Be Stored

These fields are NEVER stored because:

• The value changes based on who's viewing and from where
• You can't store 50 different values for 50 warehouses in one column

This is why you can't filter or group by "Quantity Available" - it's always calculated fresh.

Editable Computed Fields (Inverse)

Some computed fields let you edit them, and the change flows back to the source:

Field	What Happens When You Edit
Margin %	Edit margin → price updates to match
Total with Tax	Edit total → quantity adjusts
Track Date	Edit date → event timing updates

This is called an inverse - the field works in both directions.

How to Recognize Editable Computed Fields

• The field appears editable (not grayed out)
• You can type in it, and other fields change automatically
• Common in pricing, quantities, and percentage calculations

Business Scenario: When to Store Computed Fields

Scenario	Store?	Reason
Invoice total amount	Yes	Need to group invoices by amount in reports
Days until deadline	No	Changes every day, would need constant recalculation
Profit margin %	Yes	Want to filter "orders with margin > 20%"
Full address (combined)	No	Just for display, don't need to search by it
Order status	Yes	Want to filter/group orders by status

Troubleshooting Guide

Problem	Likely Cause	Solution
Field shows 0 or empty	Source fields are empty	Check if required source fields have values
Field doesn't update after change	Changed field not in depends	Try saving the record first
Field shows wrong value	Stale cached data	Refresh page, clear browser cache
Different users see different values	Context-dependent field	Check if users have different company/warehouse settings
Can't filter/group by the field	Field is not stored	Ask developer to add store=True
Field is very slow to load	Heavy computation	Developer may need to optimize or store it

When to Ask Developer for Changes

Request: "Please store this computed field"

Ask for store=True when:

• You need to filter or group by the field in list views
• The field is slow to load because calculation is complex
• You need the field in reports that query the database directly
• You want to export the field to Excel with correct values

Request: "Please add X to the depends list"

Ask for additional dependencies when:

• Changing a field doesn't trigger the expected recalculation
• You have to manually save/refresh to see updated values

Code Reference (For Developers)

# Basic computed field
total = fields.Float(
    compute='_compute_total',
    store=True,  # Save to database
)

@api.depends('quantity', 'price_unit')
def _compute_total(self):
    for record in self:
        record.total = record.quantity * record.price_unit

# Editable computed field with inverse
margin_percent = fields.Float(
    compute='_compute_margin',
    inverse='_inverse_margin',
    store=True,
    readonly=False,
)

@api.depends('cost', 'price')
def _compute_margin(self):
    for record in self:
        if record.price:
            record.margin_percent = (record.price - record.cost) / record.price * 100

def _inverse_margin(self):
    for record in self:
        if record.margin_percent and record.cost:
            record.price = record.cost / (1 - record.margin_percent / 100)

Knowledge Check

Q1: Can't Group By a computed field?

Answer: The field is not stored

Only stored fields exist in the database for SQL grouping. Ask developer to add store=True.

Q2: Computed field requires save to update?

Answer: Missing dependency

The @api.depends decorator is likely missing the field you just changed. Report to developer.

Q3: How to make a computed field editable?

Answer: Add an inverse method

An inverse method allows writing values back to the source fields, enabling two-way binding.

Q4: Why do two users see different qty_available values?

Answer: Context-dependent field

qty_available is calculated based on the user's current warehouse/company context. This is normal behavior.

Q5: A computed field is slow. What can be done?

Answer: Store it or optimize the calculation

Stored computed fields only calculate when source data changes. Non-stored fields calculate every time you view them.