EAV Attributes

Core Attribute Properties

SELECT 
    attribute_id,
    attribute_code,
    backend_type,
    frontend_input,
    frontend_label,
    is_required,
    is_filterable,
    is_searchable,
    is_used_for_sort_by,
    scope
FROM eav_attribute
WHERE entity_type_id = 4
LIMIT 15;
+---------------+---------------------+--------------+-----------------+----------------------+-------------+-------------+-------------+-------------------+-------+
| attribute_id  | attribute_code      | backend_type | frontend_input  | frontend_label       | is_required | is_filterable | is_searchable | is_used_for_sort_by | scope |
+---------------+---------------------+--------------+-----------------+----------------------+-------------+-------------+-------------+-------------------+-------+
|            71 | name                | varchar      | text            | Name                 |           1 |           0 |           0 |                 0 |     0 |
|            73 | description         | text         | textarea        | Description          |           0 |           0 |           0 |                 0 |     0 |
|            75 | price               | decimal      | price           | Price                |           1 |           0 |           0 |                 0 |     1 |
|            77 | sku                 | varchar      | text            | SKU                  |           1 |           0 |           0 |                 0 |     2 |
|            85 | small_image         | varchar      | media_image     | Small Image          |           0 |           0 |           0 |                 0 |     0 |
|            97 | status              | int          | boolean         | Status               |           1 |           1 |           0 |                 0 |     2 |
|            99 | visibility          | int          | select          | Visibility           |           1 |           1 |           0 |                 0 |     2 |
+---------------+---------------------+--------------+-----------------+----------------------+-------------+-------------+-------------+-------------------+-------+

Attribute Code Naming

Rules:
- Lowercase only
- Underscores for spaces
- No special characters
- Max 255 characters
- Must be unique per entity type

Examples:
  name              → Product name
  short_description → Short description
  special_price     → Special price
  tax_class_id      → Tax class
  news_from_date    → New from date

Backend Types

The backend_type determines which value table stores the attribute value:

-- varchar: Short text (max 255 chars)
INSERT INTO catalog_product_entity_varchar (attribute_id, entity_id, store_id, value)
VALUES (71, 123, 0, 'T-Shirt');

-- text: Long text (up to 64KB)
INSERT INTO catalog_product_entity_text (attribute_id, entity_id, store_id, value)
VALUES (73, 123, 0, 'This is a detailed product description...');

-- int: Integer values
INSERT INTO catalog_product_entity_int (attribute_id, entity_id, store_id, value)
VALUES (97, 123, 0, 1); -- status: enabled

-- decimal: Precise numeric values
INSERT INTO catalog_product_entity_decimal (attribute_id, entity_id, store_id, value)
VALUES (75, 123, 0, 29.9900); -- price

-- datetime: Date/time values
INSERT INTO catalog_product_entity_datetime (attribute_id, entity_id, store_id, value)
VALUES (101, 123, 0, '2024-01-01 00:00:00'); -- special_price_from

-- static: Stored in entity table itself
-- (e.g., type_id, attribute_set_id in catalog_product_entity)

Backend Type Selection

Input Types

-- Input types determine admin form rendering
SELECT DISTINCT frontend_input, COUNT(*) as count
FROM eav_attribute
WHERE entity_type_id = 4
GROUP BY frontend_input;
+-----------------+-------+
| frontend_input  | count |
+-----------------+-------+
| text            |    15 |
| textarea        |     5 |
| select          |    10 |
| boolean         |     3 |
| price           |     2 |
| media_image     |     3 |
| multiselect     |     2 |
| date            |     2 |
| weee            |     1 |
| weight          |     1 |
| gallery         |     1 |
+-----------------+-------+

Input Type Examples

// Text input
$eavSetup->addAttribute(
    \Magento\Catalog\Model\Product::ENTITY,
    'custom_text',
    ['type' => 'varchar', 'input' => 'text']
);

// Textarea
$eavSetup->addAttribute(
    \Magento\Catalog\Model\Product::ENTITY,
    'custom_textarea',
    ['type' => 'text', 'input' => 'textarea']
);

// Select (dropdown)
$eavSetup->addAttribute(
    \Magento\Catalog\Model\Product::ENTITY,
    'custom_select',
    ['type' => 'int', 'input' => 'select', 'source' => 'Vendor\Module\Model\Source\Options']
);

// Boolean (yes/no)
$eavSetup->addAttribute(
    \Magento\Catalog\Model\Product::ENTITY,
    'custom_boolean',
    ['type' => 'int', 'input' => 'boolean']
);

// Date
$eavSetup->addAttribute(
    \Magento\Catalog\Model\Product::ENTITY,
    'custom_date',
    ['type' => 'datetime', 'input' => 'date']
);

// Price
$eavSetup->addAttribute(
    \Magento\Catalog\Model\Product::ENTITY,
    'custom_price',
    ['type' => 'decimal', 'input' => 'price']
);

Built-in Validation

// Required validation
$eavSetup->addAttribute(
    \Magento\Catalog\Model\Product::ENTITY,
    'required_field',
    [
        'type' => 'varchar',
        'input' => 'text',
        'required' => true,
        'validate_rules' => [
            'max_text_length' => 255,
            'min_text_length' => 1
        ]
    ]
);

// Unique validation
$eavSetup->addAttribute(
    \Magento\Catalog\Model\Product::ENTITY,
    'unique_field',
    [
        'type' => 'varchar',
        'input' => 'text',
        'unique' => true
    ]
);

Custom Validation

// Custom backend model with validation
class Vendor\Module\Model\Product\Attribute\Backend\CustomValidation
    extends \Magento\Eav\Model\Entity\Attribute\Backend\AbstractBackend
{
    public function validate($object)
    {
        $value = $object->getData($this->getAttribute()->getAttributeCode());
        
        if (empty($value)) {
            throw new \Magento\Framework\Exception\LocalizedException(
                __('Field cannot be empty')
            );
        }
        
        if (strlen($value) < 3) {
            throw new \Magento\Framework\Exception\LocalizedException(
                __('Field must be at least 3 characters')
            );
        }
        
        return true;
    }
}

// Register validation
$eavSetup->addAttribute(
    \Magento\Catalog\Model\Product::ENTITY,
    'validated_field',
    [
        'type' => 'varchar',
        'input' => 'text',
        'backend' => 'Vendor\Module\Model\Product\Attribute\Backend\CustomValidation'
    ]
);

Validation Rules

// Validation rules array
'validate_rules' => [
    'max_text_length' => 255,
    'min_text_length' => 1,
    'max_number_length' => 10,
    'min_number_value' => 0,
    'max_number_value' => 100,
    'input_validation' => 'numeric',
    'email_validation' => true,
    'url_validation' => true,
]

// In di.xml
<type name="Magento\Catalog\Model\Product">
    <plugin name="validate_custom_attribute" 
            type="Vendor\Module\Plugin\ProductValidatePlugin"/>
</type>