Magento – How to completely delete EAV attribute and all its data from the database

category-attributedatabaseeav

What is the correct way to completely remove category attributes from the database?

Attributes were added this way using setup script:

$setup->addAttribute('catalog_category', 'seo_text', array(
    'group'             => 'General',
    'label'             => 'Additional Text',
    'type'              => 'text',
    'input'             => 'textarea',

    'backend'           => '',
    'frontend'          => '',
    'visible'           => true,
    'required'          => false,
    'searchable'        => false,
    'user_defined'      => true,
    'visible_on_front'  => true,
    'wysiwyg_enabled'   => false,
    'global'            => Mage_Catalog_Model_Resource_Eav_Attribute::SCOPE_STORE
));
$setup->addAttribute('catalog_category', 'cat_icon', array(
    'group'             => 'General',
    'label'             => 'Category icon',
    'type'              => 'varchar',
    'input'             => 'select',
    'source'            => 'categoryseo/source_ico',
    'backend'           => '',
    'frontend'          => '',
    'visible'           => true,
    'required'          => false,
    'searchable'        => false,
    'user_defined'      => true,
    'visible_on_front'  => true,
    'wysiwyg_enabled'   => false,
    'global'            => Mage_Catalog_Model_Resource_Eav_Attribute::SCOPE_STORE
));

Later these attributes were removed in another setup script, I used the standard code which can be found in many tutorials:

$setup = $this;
$setup->startSetup();
$setup->removeAttribute('catalog_category', 'seo_text');
$setup->removeAttribute('catalog_category', 'cat_icon');
$setup->endSetup();

This deleted the attributes from my categories. I also checked in the database and attributes were also removed from the table eav_attribute.

But data of these attributes is still stored in other tables. E.g. in table catalog_category_entity_varchar there is still info about attribute "cat_icon" for many categories.

Shouldn't all this data be automatically removed when I delete the attributes with $setup->removeAttribute(...) method? Does it mean that I have some errors in my Magento so Magento doesn't fully remove the attribute data?

Or did I just delete the attributes incorrectly? If yes, then how to do it properly? How to delete eav attributes and all the data associated with deleted attributes?

Best Answer

If you got orphan attribute values it means that there is something wrong with your database.
For example the table catalog_category_int has a constraint on the attribute_id column. 

CONSTRAINT `FK_CAT_CTGR_ENTT_INT_ATTR_ID_EAV_ATTR_ATTR_ID` FOREIGN KEY (`attribute_id`) REFERENCES `eav_attribute` (`attribute_id`) ON DELETE CASCADE ON UPDATE CASCADE,

This means that if the attribute is deleted, all the values for the attribute from the table catalog_category_int will be deleted.
It's the same for the rest of the tables (catalog_category_*).

From experience I saw that usually constraints are lost during a migration process. You export the database but without the constraints. If this is the case then remember in the future to use System->Tools->Backupto create database dumps for migration.

[EDIT]
Here is the code I've used. I've created a simple extension that adds an attribute to the category entity, I edited a category and filled in a value for that attribute, then deleted the attribute through an upgrade script.
Here are the extension files:

app/etc/module/Easylife_Attr.xml - declaration file

<?xml version="1.0"?>
<config>
    <modules>
        <Easylife_Attr>
            <codePool>local</codePool>
            <active>true</active>
            <depends>
                <Mage_Catalog />
            </depends>
        </Easylife_Attr>
    </modules>
</config>

app/code/local/Easylife/Attr/etc/config.xml - the configuration file

<?xml version="1.0"?>
<config>
    <modules>
        <Easylife_Attr>
            <version>0.0.1</version>
        </Easylife_Attr>
    </modules>
    <global>
        <resources>
            <easylife_attr_setup>
                <setup>
                    <module>Easylife_Attr</module>
                    <class>Mage_Catalog_Model_Resource_Setup</class>
                </setup>
            </easylife_attr_setup>
        </resources>
    </global>
</config>

app/code/local/Easylife/Attr/sql/easylife_attr_setup/install-0.0.1.php - the install script

<?php

$this->addAttribute('catalog_category', 'dummy', array(
    'group'         => 'General',
    'input'         => 'textarea',
    'type'          => 'text', //can be any type
    'label'         => 'Custom attribute',
    'backend'       => '',
    'visible'       => true,
    'required'      => false,
    'visible_on_front' => true,
    'global'        => Mage_Catalog_Model_Resource_Eav_Attribute::SCOPE_GLOBAL
));

Now add a value for this dummy attribute for a category.
You should see it in the table catalog_category_entity_text.

After that create an upgrade script to remove the attribute. app/code/local/Easylife/Attr/sql/easylife_attr_setup/upgrade-0.0.1-0.0.2.php 

<?php
$this->removeAttribute('catalog_category', 'dummy');

and change in config.xml the version from 0.0.1 to 0.0.2.

Refresh any page and look in the same table catalog_category_entity_text. The value that was added for the dummy attribute is gone. (at least for me).

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