Get product's category ids and names

There is this method getCategoryIds() in Mage_Catalog_Model_Resource_Eav_Mysql4_Product. This method returns all category IDs of requested product. I need to modify the SELECT statement so it will return also category names.

Here is the basic query:

$select = $this->_getReadAdapter()->select()
    ->from($this->_productCategoryTable, 'category_id')
    ->where('product_id=?', $product->getId());

I can't use catalog_category_flat table to for some reasons, so I have to use EAV tables. So at this point I have this query:

$select = $this->_getReadAdapter()->select()
    ->from($this->_productCategoryTable, 'category_id')
    ->where('catalog_category_product.product_id=?', $product->getId())
    ->join(
       array('a' =>'catalog_categ开发者_如何学JAVAory_entity_varchar'),
       'a.entity_id = catalog_category_product.category_id',
       array('name' => 'value')
    )
    ->join(
       array('b' => $this->getTable('eav/attribute')),
       'b.attribute_id = a.attribute_id',
       array()
    )
    ->where("b.attribut_code = 'name'");

This works, but I'd like to ask if there is a better way of doing it.

Easiest and probably cleanest:

$categories = $product->getCategoryCollection()
    ->addAttributeToSelect('name');

Then you can simply traverse the collection:

foreach($categories as $category) {
    var_dump($category->getName());
}

I found this post: Joining an EAV table and made the function, which will add the category join query, use it from the collection.

Just call this function from the code this way:

// To join the name of category
$this->joinCategoryAttribute('<your table alias>.category_id', 'name');

And this is the function:

public function joinCategoryAttribute($joinOriginId, $code)
{
    $attributeId = Mage::getResourceModel('eav/entity_attribute')->getIdByCode('catalog_category', $code);
    $entityType = Mage::getModel('eav/entity_type')->loadByCode('catalog_category');
    $attribute = Mage::getModel($entityType->getAttributeModel())->load($attributeId);
    $entityTable = $this->getTable($entityType->getEntityTable());
    $alias = 'table' . $code;
    $table = $entityTable . '_' . $attribute->getBackendType();
    $field = $alias . '.value';
    $this->getSelect()
        ->joinLeft(array($alias => $table),
                "{$joinOriginId} = {$alias}.entity_id AND {$alias}.attribute_id = " . $attribute->getAttributeId(),
                array($attribute->getAttributeCode() => $field)
        );
    return $this;
}