Attribute backend_type = static?

Question

Can someone explain the importance/relevance of the backend_type static for an attribute?

I am having some problems with an attribute not being loaded and I'm wondering whether this backend_type has anything to do with it?

Also, is this related in some way as to what is put in the flat tables?

Answer 1

Static attributes are attributes stored in the main table of an entity - for catalog products, catalog_product_entity. For example, the attribute sku of catalog products is defined as static. Static attributes are always loaded by Magento, and are useful especially if you want to retrieve information quickly or to optimize lookup of data. A drawback of this type of attributes is that you can't have store-specific values, which is one of the advantages of Magento EAV system.

Even if you define an attribute as static, Magento won't treat it as such unless you have a corresponding column in the main entity table. If the column is not there, Magento treats the attribute as varchar by default and looks for it in the varchar EAV table for the model - for products, catalog_product_entity_varchar.

If you want to use static attributes in your project, you have to do 2 things in your install/upgrade scripts. First, you need to add a column to the main entity table, with the correct column definition. Next, you need to install your attribute using the addAttribute() method, and define your attribute as static. Please refer to the install scripts of Mage_Catalog to better understand how things work in this case.

If you plan to run often queries based on your custom static attributes, consider adding an index on the new column to speed up data fetching.

• ahnbizcad: category_ids is static. it's not in the catalog_product_entity_varchar table.
• ahnbizcad: summary: static means the value is a column in catalog_product_entity, and if it's not, it will fall back to checking in catalog_product_entity_varchar.

Answer 2

Here is the sample from core:

$installer->run("
 ALTER TABLE `{$installer->getTable('catalog/product')}` ADD `has_options` SMALLINT(1) NOT NULL DEFAULT '0';
");
$installer->addAttribute('catalog_product', 'has_options', array(
 'type' => 'static',
 'visible'=>false,
 'default' => false
));

• Marius: What's this have to do with the question?
• Roman Snitko: @Marius this is just a sample of how to add a static attribute.
• snh_nl: Suppose you add the column directly to the DB via MySQL. How could you alter the TYPE of an existing product attribute to STATIC? Question: could we just update type=static in a certain table and it would work?