How to Update customer Attribute and which table it will be stored?

Question

I treid to create customer attribute programatically and now i want to update that the attribute with different label and type . I want to know in which table it will stored . I want to remove that attribute also.

public function install(ModuleDataSetupInterface $setup,ModuleContextInterface $context)

    {
        $eavSetup = $this->eavSetupFactory->create(['setup' => $setup]);
        $eavSetup->addAttribute(
            \Magento\Customer\Model\Customer::ENTITY,
            'phone_number',
            [
                'type'         => 'varchar',
                'label'        => 'Mobile',
                'input'        => 'integer',
                'required'     => true,
                'visible'      => true,
                'user_defined' => true,
                'position'     => 999,
                'system'       => 0,
            ]
        );
        $eavSetup->updateAttribute('customer', 'phone_number', 'type', 'varchar');
        $attribute = $this->eavConfig->getAttribute(Customer::ENTITY, 'phone_number');     
       $attribute->setData(
            'used_in_forms',
            ['adminhtml_customer', 'customer_account_create']

        );

        $attribute->save();
    }

Answer 1

The attribute itself stored eav_attribute table. please check with following SQL in mysql:

SELECT * FROM `eav_attribute` where attribute_code='phone_number';

And the values are store in customer_entity_varchar table.

SELECT * FROM `customer_entity_varchar` where attribute_id=ID_OF_ATTRIBUTE_FROM_EAV_TABLE 

If you want to upadte your Attribute then you need to add upgrade script. You cannot simply add in install script. Here is how upgrade script look like in app/code/VENDOR/MODULE/Setup/UpgradeData.php file:

<?php
namespace VENDOR\MODULE\Setup;


use Magento\Framework\Setup\ModuleDataSetupInterface;
use Magento\Framework\Setup\UpgradeDataInterface;
use Magento\Framework\Setup\ModuleContextInterface;
use Magento\Eav\Setup\EavSetupFactory;

class UpgradeData implements UpgradeDataInterface
{

    public function __construct(EavSetupFactory $eavSetupFactory)
    {
        $this->eavSetupFactory = $eavSetupFactory;
    }

    public function upgrade(ModuleDataSetupInterface $setup, ModuleContextInterface $context)
    {
        $setup->startSetup();

        //handle all possible upgrade versions

        if (!$context->getVersion()) {
            $setup->endSetup();
        }
        if (version_compare($context->getVersion(), '2.1.0') < 0) { //VERSION OF YOUR MODULE in module.xml
            $eavSetup = $this->eavSetupFactory->create(['setup' => $setup]);
            $objectManager = \Magento\Framework\App\ObjectManager::getInstance();
            /** @var \Magento\Eav\Model\ResourceModel\Entity\Attribute $attribute */
            $attribute = $objectManager->create('\Magento\Eav\Model\ResourceModel\Entity\Attribute');
            $attributeId = $attribute->getIdByCode('customer','phone_number');

            $eavSetup->updateAttribute(
                1,
                $attributeId,
                'type',
                'varchar'
            );
        }
    }
}

Answer 2

The customer attribute you have created is stored in the table customer_entity_varchar as you had declared in your code with the "type" property. Another reference to that attribute is going to be stored at customer_entity with the entity_id as a reference.

Answer 3

the only thing that worked for me was to use the getConnection function in an upgrade data script like this:

$setup->startSetup();

if (version_compare($context->getVersion(), '2.1.8', '<'))
{

$attribute_id = $this->_eavAttribute->getIdByCode('customer', 'attribute_code');
$setup->getConnection()->update($setup->getTable('eav_attribute'),
['is_required' => false], 'attribute_id=' . $attribute_id);
}

$setup->endSetup();