How to create an attribute in Magento 1.9?

Question

I am new to Magento and I am creating a product attribute but the problem I have is that I have 3 Attribute Sets (default, Imported, Local), but when I create the attribute, this attribute is created in the 3 Attribute Sets, even if I do not have the created group, the attribute creates it automatically.

$this->startSetup();    
$this->addAttribute('catalog_product', 'cod_import', array(
    'label'             => 'Código de Importación',
    'attribute_set'     => 'Importados',
    'group'             => 'Especificaciones de importacion',
    'type'              => 'decimal',
    'visible'           => true,
    'required'          => true,
    "nullable"          => true,
    'sort_order'        => 2
));
$this->endSetup();

Answer 1

You cannot define the attribute set when creating the attribute with this method. Change group to undefined and set user_defined as true to create an attribute without setting an attribute set. After creating it, add the attribute to an attribute set in the upgrade or setup script.

Answer 2

You can do it as part of install script

/** 
* Add blank attibute set 
*/ 
$attibuteSet = new Mage_Eav_Model_Entity_Setup('core_setup'); 
/* @var $attibuteSet Mage_Eav_Model_Entity_Setup */ 
$attibuteSet->startSetup(); 
$attibuteSet->addAttributeSet( 
    Mage_Catalog_Model_Product::ENTITY, 'Custom' 
); 
$attibuteSet->endSetup(); 


/** 
* Add attibute set based on default set 
*/ 
$attibuteSet = new Mage_Catalog_Model_Resource_Setup('core_setup'); 
$attibuteSet->startSetup(); 
$defaultAttributeSetId  = $attibuteSet->getAttributeSetId(Mage_Catalog_Model_Product::ENTITY, 'Default'); 
$entityTypeId           = $attibuteSet->getEntityTypeId(Mage_Catalog_Model_Product::ENTITY); 
$attributeSetsName      = array('CustomTwo'); 


foreach ($attributeSetsName as $attributeSetName) { 

    $model  = Mage::getModel('eav/entity_attribute_set')->setEntityTypeId($entityTypeId); 
    $model->setAttributeSetName($attributeSetName); 


try { 
        if ($model->validate()) { 
            $model->save(); 
            $model->initFromSkeleton($defaultAttributeSetId); 
            $model->save(); 
        } 
    } catch (Exception $e) { 
        Mage::logException($e); 
    } 
} 
$attibuteSet->endSetup(); 


/** 
* Add Attibute 
*/ 
$addAttribute = new Mage_Catalog_Model_Resource_Setup('core_setup'); 
/* @var $attribute Mage_Catalog_Model_Resource_Setup */ 
$productTypes = array( 
    Mage_Catalog_Model_Product_Type::TYPE_SIMPLE, 
    Mage_Catalog_Model_Product_Type::TYPE_CONFIGURABLE, 
); 


$addAttribute->startSetup(); 


if (!$addAttribute->getAttributeId(Mage_Catalog_Model_Product::ENTITY, 'custom_attribute')) { 
    $addAttribute->addAttribute( 
        Mage_Catalog_Model_Product::ENTITY,  
        'custom_attribute',  
            array(          // TABLE.COLUMN:                                       DESCRIPTION: 
            'label'                      => 'Custom Attribute',                                       // eav_attribute.frontend_label                        admin input label 
            'group'                      => 'General',                                                // (not a column)                                      tab in product edit screen 
            'sort_order'                 => 0,                                                        // eav_entity_attribute.sort_order                     sort order in group 
            'backend'                    => '',                                                       // eav_attribute.backend_model                         backend class (module/class_name format) 
            'type'                       => 'varchar',                                                // eav_attribute.backend_type                          backend storage type (varchar, text etc) 
            'frontend'                   => '',                                                       // eav_attribute.frontend_model                        admin class (module/class_name format) 
            'note'                       => null,                                                     // eav_attribute.note                                  admin input note (shows below input) 
            'default'                    => null,                                                     // eav_attribute.default_value                         admin input default value 
            'wysiwyg_enabled'            => false,                                                    // catalog_eav_attribute.is_wysiwyg_enabled            (products only) admin input wysiwyg enabled 
            'input'                      => 'text',                                                   // eav_attribute.frontend_input                        admin input type (select, text, textarea etc) 
            'input_renderer'             => false,                                                    // catalog_eav_attribute.frontend_input_renderer       (products only) admin input renderer (otherwise input is used to resolve renderer) 
            'source'                     => null,                                                     // eav_attribute.source_model                          admin input source model (for selects) (module/class_name format) 
            'required'                   => false,                                                    // eav_attribute.is_required                           required in admin 
            'user_defined'               => true,                                                     // eav_attribute.is_user_defined                       editable in admin attributes section, false for not 
            'unique'                     => false,                                                    // eav_attribute.is_unique                             unique value required 
            'global'                     => Mage_Catalog_Model_Resource_Eav_Attribute::SCOPE_GLOBAL,  // catalog_eav_attribute.is_global                     (products only) scope 
            'visible'                    => true,                                                     // catalog_eav_attribute.is_visible                    (products only) visible on admin 
            'visible_on_front'           => false,                                                    // catalog_eav_attribute.is_visible_on_front           (products only) visible on frontend (store) attribute table 
            'used_in_product_listing'    => false,                                                    // catalog_eav_attribute.used_in_product_listing       (products only) made available in product listing 
            'searchable'                 => false,                                                    // catalog_eav_attribute.is_searchable                 (products only) searchable via basic search 
            'visible_in_advanced_search' => false,                                                    // catalog_eav_attribute.is_visible_in_advanced_search (products only) searchable via advanced search 
            'filterable'                 => false,                                                    // catalog_eav_attribute.is_filterable                 (products only) use in layered nav 
            'filterable_in_search'       => false,                                                    // catalog_eav_attribute.is_filterable_in_search       (products only) use in search results layered nav 
            'comparable'                 => false,                                                    // catalog_eav_attribute.is_comparable                 (products only) comparable on frontend 
            'is_html_allowed_on_front'   => false,                                                    // catalog_eav_attribute.is_visible_on_front           (products only) seems obvious, but also see visible 
            'apply_to'                   => join(',', $productTypes),                                 // catalog_eav_attribute.apply_to                      (products only) which product types to apply to 
            'is_configurable'            => true,                                                     // catalog_eav_attribute.is_configurable               (products only) used for configurable products or not 
            'used_for_sort_by'           => false,                                                    // catalog_eav_attribute.used_for_sort_by              (products only) available in the 'sort by' menu 
            'position'                   => 0,                                                        // catalog_eav_attribute.position                      (products only) position in layered naviagtion 
            'used_for_promo_rules'       => false,                                                    // catalog_eav_attribute.is_used_for_promo_rules       (products only) available for use in promo rules 
        ) 
    ); 
} 


$addAttribute->endSetup(); 


/** 
* Add Attibute To Set 
*/ 


$addAttributeToSet = new Mage_Catalog_Model_Resource_Setup('core_setup'); 
/* @var $addAttributeToSet Mage_Catalog_Model_Resource_Setup */ 


$attributeId        = $addAttributeToSet->getAttributeId(Mage_Catalog_Model_Product::ENTITY, 'custom_attribute'); 
$attributeSetId     = $addAttributeToSet->getAttributeSetId(Mage_Catalog_Model_Product::ENTITY, 'Custom'); 
$attributeGroupId   = $addAttributeToSet->getAttributeGroup(Mage_Catalog_Model_Product::ENTITY, $attributeSetId, 'General'); 
$addAttributeToSet->addAttributeToSet( 
    Mage_Catalog_Model_Product::ENTITY,  
    $attributeSetId,  
    $attributeGroupId,  
    $attributeId 
); 


$addAttributeToSet->endSetup();