> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mercurjs.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Data models

> The data models owned by the Attribute (Product Attribute) domain.

The Attribute domain is owned by the **Product Attribute module**. This reference
lists its data models and their fields. For the full module overview, see the
[Attribute module overview](/platform/attribute/overview).

## ProductAttribute

Table `product_attribute`, id prefix `pattr`. A typed catalog attribute.

| Field               | Type    | Notes                                                                      |
| ------------------- | ------- | -------------------------------------------------------------------------- |
| `id`                | text    | Primary key                                                                |
| `name`              | text    | Searchable                                                                 |
| `handle`            | text    | Nullable; unique when set                                                  |
| `description`       | text    | Nullable                                                                   |
| `type`              | enum    | `AttributeType`: `single_select`, `multi_select`, `text`, `unit`, `toggle` |
| `is_required`       | boolean | Default `false`                                                            |
| `is_filterable`     | boolean | Default `false`; exposes the attribute as a storefront filter              |
| `is_variant_axis`   | boolean | Default `false`; `multi_select` axis that generates variants               |
| `rank`              | number  | Default `0`; ordering                                                      |
| `is_active`         | boolean | Default `true`                                                             |
| `created_by`        | text    | Nullable                                                                   |
| `product_id`        | text    | Nullable; non-null = product-scoped (inline), null = global                |
| `product_option_id` | text    | Nullable; FK to the mirror `ProductOption` (axis attributes)               |
| `metadata`          | json    | Nullable                                                                   |

Relations: `values` (one-to-many `ProductAttributeValue`, deleted with the
attribute).

## ProductAttributeValue

Table `product_attribute_value`, id prefix `pattrval`. A selectable value that
belongs to one attribute.

| Field                     | Type    | Notes                                                         |
| ------------------------- | ------- | ------------------------------------------------------------- |
| `id`                      | text    | Primary key                                                   |
| `name`                    | text    | The value label                                               |
| `handle`                  | text    | Nullable; unique per attribute when set                       |
| `rank`                    | number  | Default `0`; ordering                                         |
| `is_active`               | boolean | Default `true`                                                |
| `product_option_value_id` | text    | Nullable; FK to the mirror `ProductOptionValue` (axis values) |
| `metadata`                | json    | Nullable                                                      |

Relations: `attribute` (belongs to `ProductAttribute` via `attribute_id`).

<Note>
  `product_option_id` on the attribute and `product_option_value_id` on the value
  are the foreign keys behind the read-only mirror links to Medusa's product
  options. See [Links](/platform/attribute/reference/links).
</Note>