Ttdfjt

I have seen Magento enterprise reward points module created new backend_type integer for following fields in eav_attribute table.
reward_points_balance_refunded,reward_salesrule_points.

How we can create new backend_type and store into that particular table

Two samples here using InstallData script, you can add an attribute during or upon installation of your custom module.

Adding Product Attribute

<?php
namespace vendormoduleSetup;

use MagentoEavSetupEavSetup;
use MagentoEavSetupEavSetupFactory;
use MagentoFrameworkSetupInstallDataInterface;
use MagentoFrameworkSetupModuleContextInterface;
use MagentoFrameworkSetupModuleDataSetupInterface;

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(
 MagentoCatalogModelProduct::ENTITY,
 'sample_attribute',
 [
 'type' => 'text',
 'backend' => '',
 'frontend' => '',
 'label' => 'Sample Atrribute',
 'input' => 'text',
 'class' => '',
 'source' => '',
 'global' => MagentoEavModelEntityAttributeScopedAttributeInterface::SCOPE_GLOBAL,
 'visible' => true,
 'required' => true,
 'user_defined' => false,
 'default' => '',
 'searchable' => false,
 'filterable' => false,
 'comparable' => false,
 'visible_on_front' => false,
 'used_in_product_listing' => true,
 'unique' => false,
 'apply_to' => ''
 ]
 );
 
 

Adding Customer Attribute

<?php

namespace vendormoduleSetup;

use MagentoEavSetupEavSetup;
use MagentoEavSetupEavSetupFactory;
use MagentoFrameworkSetupInstallDataInterface;
use MagentoFrameworkSetupModuleContextInterface;
use MagentoFrameworkSetupModuleDataSetupInterface;
use MagentoEavModelConfig;
use MagentoCustomerModelCustomer;

class InstallData implements InstallDataInterface

 private $eavSetupFactory;

 public function __construct(EavSetupFactory $eavSetupFactory, Config $eavConfig)
 
 $this->eavSetupFactory = $eavSetupFactory;
 $this->eavConfig = $eavConfig;
 

 public function install(ModuleDataSetupInterface $setup, ModuleContextInterface $context)
 
 $eavSetup = $this->eavSetupFactory->create(['setup' => $setup]);
 $eavSetup->addAttribute(
 MagentoCustomerModelCustomer::ENTITY,
 'sample_attribute',
 [
 'type' => 'varchar',
 'label' => 'Sample Attribute',
 'input' => 'text',
 'required' => false,
 'visible' => true,
 'user_defined' => true,
 'position' => 999,
 'system' => 0,
 ]
 );
 $sampleAttribute = $this->eavConfig->getAttribute(Customer::ENTITY, 'sample_attribute');

 // more used_in_forms ['adminhtml_checkout','adminhtml_customer','adminhtml_customer_address','customer_account_edit','customer_address_edit','customer_register_address']
 $sampleAttribute->setData(
 'used_in_forms',
 ['adminhtml_customer']

 );
 $sampleAttribute->save();