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Magento - How to create "decimal" attribute type

I've done a bit of searching online but I have not found any answers to this question yet. I have a situation where I need a product attribute that is a decimal value and it must support negative numbers as well as positive and must also be sortable. For some reason, Magento does not have a "decimal" attribute type. The only type that uses decimal values is Price, but that doesn't support negative numbers. If I use "text" as the type, it supports whatever I want, but it doesn't sort properly because it sees the values as strings rather than floating point numbers. I have been able to work around this issue, as others have in posts I've found, by manually editing the eav_attribute table and changing 'frontend_input' from 'price' to 'text', but leaving the 'backend_type' as 'decimal'. This works great...until someone edits the attribute in the admin panel. Once you save the attribute, Magento notices that the frontend_input is 'text' and changes the 'backend_type' to 'varchar'. The only way around this that I can think of is by creating a custom attribute type, but I'm not sure where to start and I can't find any details online for this.

Has anyone else experienced this problem? If so, what have you done to correct it? If I need to create a custom attribute type, do you have any tips or can you point me at any tutorials out there for doing this?

Thanks!

like image 399
Mageician Avatar asked Aug 20 '12 18:08

Mageician


1 Answers

What you want to do is create a custom attribute type.

This can be done by first creating a installer script (this updates the database).

startSetup();

$installer->addAttribute('catalog_product', 'product_type', array(
    'group'             => 'Product Options',
    'label'             => 'Product Type',
    'note'              => '',
    'type'              => 'dec',    //backend_type
    'input'             => 'select', //frontend_input
    'frontend_class'    => '',
    'source'            => 'sourcetype/attribute_source_type',
    'backend'           => '',
    'frontend'          => '',
    'global'            => Mage_Catalog_Model_Resource_Eav_Attribute::SCOPE_WEBSITE,
    'required'          => true,
    'visible_on_front'  => false,
    'apply_to'          => 'simple',
    'is_configurable'   => false,
    'used_in_product_listing'   => false,
    'sort_order'        => 5,
));

$installer->endSetup();

After that you need to create a custom php class named:

Whatever_Sourcetype_Model_Attribute_Source_Type

And in there paste this in:

class Whatever_Sourcetype_Model_Attribute_Source_Type extends Mage_Eav_Model_Entity_Attribute_Source_Abstract
{
    const MAIN = 1;
    const OTHER = 2;

public function getAllOptions()
{
    if (is_null($this->_options)) {
        $this->_options = array(
            array(
                'label' => Mage::helper('sourcetype')->__('Main Product'),
                'value' =>  self::MAIN
            ),
            array(
                'label' => Mage::helper('sourcetype')->__('Other Product'),
                'value' =>  self::OTHER
            ),
        );
    }
    return $this->_options;
}

public function toOptionArray()
{
    return $this->getAllOptions();
}

public function addValueSortToCollection($collection, $dir = 'asc')
{
    $adminStore  = Mage_Core_Model_App::ADMIN_STORE_ID;
    $valueTable1 = $this->getAttribute()->getAttributeCode() . '_t1';
    $valueTable2 = $this->getAttribute()->getAttributeCode() . '_t2';

    $collection->getSelect()->joinLeft(
        array($valueTable1 => $this->getAttribute()->getBackend()->getTable()),
        "`e`.`entity_id`=`{$valueTable1}`.`entity_id`"
        . " AND `{$valueTable1}`.`attribute_id`='{$this->getAttribute()->getId()}'"
        . " AND `{$valueTable1}`.`store_id`='{$adminStore}'",
        array()
    );

    if ($collection->getStoreId() != $adminStore) {
        $collection->getSelect()->joinLeft(
            array($valueTable2 => $this->getAttribute()->getBackend()->getTable()),
            "`e`.`entity_id`=`{$valueTable2}`.`entity_id`"
            . " AND `{$valueTable2}`.`attribute_id`='{$this->getAttribute()->getId()}'"
            . " AND `{$valueTable2}`.`store_id`='{$collection->getStoreId()}'",
            array()
        );
        $valueExpr = new Zend_Db_Expr("IF(`{$valueTable2}`.`value_id`>0, `{$valueTable2}`.`value`, `{$valueTable1}`.`value`)");

    } else {
        $valueExpr = new Zend_Db_Expr("`{$valueTable1}`.`value`");
    }



    $collection->getSelect()
        ->order($valueExpr, $dir);

    return $this;
}

public function getFlatColums()
{
    $columns = array(
        $this->getAttribute()->getAttributeCode() => array(
            'type'      => 'int',
            'unsigned'  => false,
            'is_null'   => true,
            'default'   => null,
            'extra'     => null
        )
    );
    return $columns;
}


public function getFlatUpdateSelect($store)
{
    return Mage::getResourceModel('eav/entity_attribute')
        ->getFlatUpdateSelect($this->getAttribute(), $store);
}
}

Hope this helps.

For further info see here.

like image 185
pzirkind Avatar answered Nov 11 '22 17:11

pzirkind