Save product textarea attribute without changing updated_at field?

Question

I'm writing a script that will be run every hour to update a field of any product updated in the last hour. The script itself works, but it also updates the updated_at field upon saving the product.

After doing some research, I found that the best way to update the single field would be to use a direct sql statement to modify that single field.

So, I have the product id, the attribute id, and the new attribute value. The attribute uses a textarea as its input. I don't know which table to write the change to.

For example, if product_id is 1234 and attribute_id is 567, what would the sql statement look like? Something like this?

$val = "Some generated value.";
$connection = Mage::getSingleton('core/resource')->getConnection('core_write');
$sql = 'UPDATE `<insert table name here>` SET `value` = ? WHERE `entity_id` = ? AND `attribute_id` = ?';
$connection->query($sql, array($val, 1234, 567));

Also, is there some kind of reference for this sort of thing that I can look at in the future?

Answer 1

The EAV tables responsible for saving the values of Magento product attributes are :

catalog_product_entity_datetime
catalog_product_entity_decimal
catalog_product_entity_gallery
catalog_product_entity_group_price
catalog_product_entity_int
catalog_product_entity_media_gallery
catalog_product_entity_media_gallery_value
catalog_product_entity_text
catalog_product_entity_tier_price
catalog_product_entity_varchar

In your case, depending on the type you chose for the attribute, it will be _text, to hold as much data as possible from the text area field.

An example would be, the description field in a product. knowing that the product entity type ID and the attribute code, I can get the details of it from eav_attribute :

SELECT * FROM eav_attribute where attribute_code = 'description' AND entity_type_id = '4' \G

Which will show me the backend_type

   attribute_id: 64
 entity_type_id: 4
 attribute_code: description
attribute_model: NULL
  backend_model: NULL
   **backend_type: text**
  backend_table: NULL
 frontend_model: NULL
 frontend_input: textarea
 frontend_label: Description
 frontend_class: NULL
   source_model: NULL
    is_required: 1
is_user_defined: 0
  default_value: NULL
      is_unique: 0

From there, I will be able to determine where the data is saved for a specific entity, which leads to your question again, now I can be able to get the value by:

SELECT * FROM catalog_product_entity_text WHERE entity_id='1234' AND attribute_id='567' \G

Or update it with:

UPDATE catalog_product_entity_text SET value='My New Value' WHERE entity_id='1234' AND attribute_id='567'

Please note, that there is also a store_id which you have to take into consideration, if you have content per store.