Custom Attribute is not saving data in database

Question

I'm trying to add custom text box named cashback in Magento 2 product add/edit page. I added the text box programmatically. But my below code doesn't add column in the table also not saving the value. I'm a beginner so I can't understand Magento 2 structure. I need clarification about which table does it stores and need to store data given in admin panel.

<?php

namespace Rk\Wallet\Setup;

use Magento\Eav\Setup\EavSetup;
use Magento\Eav\Setup\EavSetupFactory;
use Magento\Framework\Setup\InstallDataInterface;
use Magento\Framework\Setup\ModuleContextInterface;
use Magento\Framework\Setup\ModuleDataSetupInterface;

class InstallData implements InstallDataInterface
{
    private $eavSetupFactory;
    public function __construct(
        EavSetupFactory $eavSetupFactory
    )
    {
        $this->eavSetupFactory = $eavSetupFactory;
    }

    public function install(ModuleDataSetupInterface $setup, ModuleContextInterface $context)
    {
        $eavSetup = $this->eavSetupFactory->create(['setup' => $setup]);
        $eavSetup->addAttribute(
          "cashback",
          [
          'group' => "",
          'label' => "Cashback",
          'is_html_allowed_on_front' => true,
          'default' => '1',
          'note' => '',
          'global' => \Magento\Catalog\Model\ResourceModel\Eav\Attribute::SCOPE_STORE,
          'visible' => true,
          'required' => false,
          'user_defined' => true,
          'searchable' => true,
          'filterable' => true,
          'comparable' => false,
          'visible_on_front' => true,
          'visible_in_advanced_search' => false,
          'unique' => false,
          "frontend_class" => "cashbackclass",
          "used_in_product_listing" => true,
          "type"                    => "int",
          "input" => "text",
          "type" => "int",
          "source" => "Vendor\Module\Model\Config\Source\TimeSetup",
          'backend' => 'Magento\Eav\Model\Entity\Attribute\Backend\ArrayBackend'
          ]
      );
    }
}

Answer 1

Magento 2 stores setup data/schema versions in setup_module table. I think that first what you have done was to run setup:upgrade after you added module and according version was set in table.

InstallData/Schema scripts are run only when there is no version stored in db, so at the first run of setup upgrade. If my assumption is correct then either remove relevant entry in setup_module table or put your script into UpgradeData and update module's version in etc/module.xml to higher.

Check other UpgradeData scripts to see how you can compare versions.

Answer 2

There are some errors in your script. please try this.

public function install(ModuleDataSetupInterface $setup, ModuleContextInterface $context) {
        /** @var EavSetup $eavSetup */
        $eavSetup = $this->eavSetupFactory->create(['setup' => $setup]);

        $eavSetup->addAttribute(
                \Magento\Catalog\Model\Product::ENTITY, 'cashback', [
            'group' => 'Product Details',
            'type' => 'text',
            'sort_order' => 102,
            'backend' => '',
            'frontend' => '',
            'label' => 'CashBack',
            'input' => 'textarea',
            'class' => '',
            'source' => 'Magento\Eav\Model\Entity\Attribute\Source\Boolean',
            'global' => \Magento\Catalog\Model\ResourceModel\Eav\Attribute::SCOPE_GLOBAL,
            'visible' => true,
            'required' => false,
            'user_defined' => true,
            'default' => '',
            'searchable' => true,
            'filterable' => true,
            'comparable' => false,
            'visible_on_front' => true,
            'used_in_product_listing' => true,
            'unique' => false,
            'apply_to' => 'simple,configurable,virtual,bundle,downloadable'
        ]);
    }

Note: Remove the entry of your module from setup_module table. Also check the attribute named cashback in eav_attribute table. If you find one, remove that as well.