Magento EAV: how to hard delete an attribute value? - magento

Question

Let's ask the question clearly before entering into the details:
Is there a way of hard deleting an attribute value from a product?
By hard I mean, removing the row from the database and not only setting the value to null or empty.
Now, the details:
I'm currently confronted to a problem on Magento.
Many product in my store have user defined attributes that are not related to the product. For example, let's say we have a bag product, among other products like t-shirts,dresses,pants,etc.:
Our bag product has only configurable 1 attribute: color.
Our T-Shirt product has 2 configurable attributes: color and tshirt_size.
Our Dress product has 2 configurable attributes: color and dress_size
My current problem is that when I retrieve my Bag product from the database, the attributes stored in my product are: color, tshirt_size and dress_size.
I suspect that it is because on our store you can change the attribute set of a product (thanks to the FlagBit ChangeAttributeSet community extension).
I think that the bag product has been created with a specific attribute set, then someone changed the attribute set to another, and another again. That would have lead the product to get ALL the attributes from ALL the attribute sets it has been changed to. But that's just a though, and it could be another reason. I'm actually currently not looking for the specific reason that led my product to have unrelated attributes.
I today want to reset my products. By reset I mean removing the attributes unrelated to my product. In the case of my bag, that means removing the tshirt_size and dress_size attributes. And by removing I mean deleting forever these attributes from the object.
My problem is that, I can't find how to do it. I tried setting the attributes to NULL and saving the product, but when I query again the product, I still get the attribute in the datas, with a null value. I don't want the attribute value to be null, I want the attribute to not exist.
Here is a sample of code that explains a bit what I tried:
$product = Mage::getModel('catalog/product')->load(1234); //Let's assume that my bag product ID is 1234
Mage::log($product->getData());
/* This last line dump all my products datas and contains among other things:
[...]=>...
[color]=>3
[tshirt_size]=>34
[dress_size]=>45
[...]=>...
*/
If I do a:
$product->setData('tshirt_size',null);
$product->setData('dress_size',null);
$product->save();
then again:
$product = Mage::getModel('catalog/product')->load(1234);
Mage::log($product->getData());
/* I get:
[...]=>...
[color]=>3
[tshirt_size]=>null
[dress_size]=>null
[...]=>...
*/
I don't want that. I want:
/*
[...]=>...
[color]=>3
[...]=>...
*/
The fact that I still have the entries in my array mean that the actual rows in the database are not deleted. I want the rows to be deleted.
Even more frustrating, when I do a:
$product->getAttributes();
It returns me all the attributes that can be set to my product without the unrelated attributes -which makes sense because the unrelated attributes are not in the attribute set of my product.
So, again, the question is:
Is there a way of hard deleting an attribute value from a product?
By hard I mean, removing the row from the database and not only setting the value to null or empty.
Thanks for your help!
Hugues.
FYI: I'm using Magento 1.6.1.0 (but it does not really change anything)

Answer 1

I finally had to tackle this, and although #vBuck was close, I always was able to query the old data after the switch in the attribute set and if I switched back I would see the old data when it shouldn't have been there. Today, I have the same need to ensure the random data is removed. Here is how I approached this topic.
In order to programmatically delete attributes when you switch from one set to another you must first look at all the entries for the new set, then get a list of all attributes, check against that list and (this is the important part) remove it from the correct entity table. For example, I want to get rid of a value of 500 GB that is in the sample Magento data when I switch Western Digital 500GB HD - 7200RPM from Hard Drive to Shoes. In order to do that I must remove the entry in the catalog_product_entity_text table it's stored at. This means that I must find that entry where it's equal to the product id and then delete it from it's entity type table.
I was able to do this, and was not able to find the stray data after. This was confirmed by both a DB search and switching back to the old attribute set and looking for the data. you can find it all here
https://gist.github.com/jeremyBass/6581038#file-attribute-clean-switch-md
TESTED in CE 1.7.0.2, 1.8.0.0

Answer 2

So I too would love to have the programmatic answer, but I don't have the time to do it. But this is what I can provide to this chain. You see the desired resulting action happening when you try to remove an attribute by its self from the admin.
Steps:
make sure the attr set has the attr in it's set.
update all products with that attr set to have the attr needing deletion as null.
remove the the attr from the set
Seems when I don't clear all attrs before removal of attr from the set, the result is for the app to leave the rows there. Maybe for safety, I don't know as I have not dived in. What I can tell with as little as I have looked in this it’s that if you don't clear the values before attr removal from the set, when you set the attr to null, the attr remains.
So, then the programmatic solutions will need to follow that pattern. If I get time I'll write it, but I have like 15 other tasks in the queue right now.

Answer 3

Ok, I found it finally, 15 minutes after asking the question (and spending few hours trying to solve it)
Here is the answer:
$product = Mage::getModel('catalog/product')->load(1234); //Let's assume that my bag product ID is 1234
$product->setData('unwanted_attribute',null);
$resource = $product->getResource();
$resource->saveAttribute($product,'unwanted_attribute');
Edit: This doesn't work. If you re-save the product later by doing a $product->save(), all the attributes reappear.

Answer 4

Looks like this is an old post, but I too was looking for an answer here, and I think I'm onto a solution.
To solve this, I had to work directly with the product resource's write adapter:
$product->getResource()->getWriteConnection()
to delete the attribute values from the table.
I got clues on how to do this after digging through some code. See Mage_Catalog_Model_Resource_Eav_Mysql4_Abstract::_saveAttributeValue:
$write = $this->_getWriteAdapter();
$storeId = Mage::app()->getStore($object->getStoreId())->getId();
$table = $attribute->getBackend()->getTable();
/**
* If we work in single store mode all values should be saved just
* for default store id
* In this case we clear all not default values
*/
if (Mage::app()->isSingleStoreMode()) {
$storeId = $this->getDefaultStoreId();
$write->delete($table, join(' AND ', array(
$write->quoteInto('attribute_id=?', $attribute->getAttributeId()),
$write->quoteInto('entity_id=?', $object->getEntityId()),
$write->quoteInto('store_id<>?', $storeId)
)));
}
By using this code in a loop through $product->getAttributes() before changing the attribute set, you are able to "unlink" the values from the attributes of the product without destroying the attributes themselves. Then you can change the attribute set (as done in Flagbit's extension) safely, not leaving behind dead data.
Using the above code, here's a demonstration that I've written to prove my theory:
$product=Mage::getModel('catalog/product')->load(MY_TARGET_PRODUCT_ID);
$write=$product->getResource()->getWriteConnection();
foreach($product->getAttributes() as $attribute) {
if($attribute->getId()==MY_TARGET_ATTRIBUTE_ID) {
$write->delete(
$attribute->getBackend()->getTable(),
join(' AND ', array(
$write->quoteInto('attribute_id=?',$attribute->getAttributeId()),
$write->quoteInto('entity_id=?',$product->getId())
))
);
}
}
In this example, I'm looking for a specific attribute to clear from the product, but you can remove the IF conditional to delete every attached value.
I haven't fully tested this, but so far it seems alright. I'm running Magento 1.4, by the way. Hope it helps someone!
UPDATE:
Looks like the above is only half correct. You'll still have to be careful not to clear certain attributes that might render the product dead (such as the name, mode, status, and others). So in my case, it looks like I'll have to compare with the default attribute set before removing.
ANOTHER UPDATE:
With the help of this SO post: https://stackoverflow.com/a/8500506/1442685
I was able to compare all attributes linked to a product and delete only the non-default values. This way, when changing sets, I can ensure that basic information about the product is not lost. Check out my Gist for the two classes which make it all happen:
https://gist.github.com/vbuck/5911170

Answer 5

You should be able to unset the value like either of these:
$product->unsetData('unwanted_attribute')
->save();
$product->unsUnwantedAttribute()
->save();

Answer 6

you need to go to admin>>catalog>>attributes>>manage attribute sets
if your trying to manage your product catalog you should first think of your attributes (separate to your product), then your sets(again not actually part of your products).
after you have properly established your attributes and sets (of attributes) you can apply them to products with values for each attribute.
or maybe you prefer this kinda thing?
class Mage_catalog_Model_Product_Attribute_Set_Api extends Mage_Api_Model_Resource_Abstract
{
{
/**
* Retrieve attribute set list
*
* #return array
*/
public function items()
{
$entityType = Mage::getModel('catalog/product')->getResource()->getEntityType();
$collection = Mage::getResourceModel('eav/entity_attribute_set_collection')
->setEntityTypeFilter($entityType->getId());
$result = array();
foreach ($collection as $attributeSet) {
$result[] = array(
'set_id' => $attributeSet->getId(),
'name' => $attributeSet->getAttributeSetName()
);
}
return $result;
}
} // Class Mage_Catalog_Model_Product_Attribute_Set_Api End

Answer 7

Once you have associated an attribute set to a product there is no way to change attribute set or remove that attribute set.
The way out is to export product and then modify sheet and import.
This link also explains :
https://collaborate.magento.com/magento/topics/how_do_i_change_product_attribute_set