Computed Columns

A computed column shows a value that is not stored — the last order date of a customer, the number of open invoices. Instead of naming an attribute, the list column or detail field names a method of the model:

# lists/customers-list.yml
columns:
  - field: name
    label: Name
  - field: last_order
    label: Last order
    type: date
    method: lastOrder

# details/customer-detail.yml
fields:
  - name: detailData.last_order
    label: Last order
    type: date
    method: lastOrder

use Carbon\CarbonInterface;
use Noerd\Attributes\ComputedValue;

class Customer extends Model
{
    #[ComputedValue(with: ['orders'])]
    public function lastOrder(): ?CarbonInterface
    {
        return $this->orders->max('created_at');
    }
}

• field (list) or name (detail) names the value. In a list it must not be a table column; the value is exposed under that name on every row.
• type formats the result like any other column or field: date, datetime, number, currency, bool, or text when omitted.
• method names the model method that computes it.

The Marker

Only a method that carries #[Noerd\Attributes\ComputedValue] is called. It must also be public and non-static, and take no required parameters. This is checked by reflection before the call.

Anything else renders empty and is logged as Computed column method not allowed. That covers a typo, an unmarked method, delete() and save(), so a YAML entry can never trigger a side effect.

with: names the relations the method reads. A list eager-loads them once per page, so the method does not issue one query per row. A detail loads them with loadMissing().

Return Values

The method may return a scalar, a DateTimeInterface, a BackedEnum (its value) or a Stringable. The column type decides the presentation:

type	Shown as
date / datetime	the date (Y-m-d / Y-m-d H:i:s, then formatted in the reader's locale)
number / currency	a number
bool	Yes/No
anything else	the value as text

Any other return value, such as a model or an array, is blank. An exception thrown by the method renders the value blank and is logged as Computed column method failed, so it never breaks a list or a form.

In Lists

• The values are computed once per page for all rows, and once per chunk in the CSV export.
• A method runs in PHP after the page has been loaded, so a method column is display only. It is added to notSortableColumns, gets no filter funnel and is never searched.

In Detail Forms

• The value is computed for the saved record before every render, so it is fresh after a save. A new record shows the field empty.
• The value lives in the component property $computedValues, never in $detailData. The field is re-bound to computedValues.{key}, so no store path can persist it — neither the default one nor a custom store() — and required: is ignored.
• It always renders as text in the display theme, formatted by the field type.

Further Providers

method: is computed by Noerd\Support\ModelMethodColumns, the provider the core registers on Noerd\Services\ComputedColumnRegistry. A package can register a provider of its own that recognises another YAML key. That provider may also make its columns sortable and filterable, e.g. through subselects. See Extension Registries.