Magento 2 how to create link_title column for the table catalog_product_link

Question

How to create column called link_title to the catalog_product_link table & what are the steps, need to be followed to set the value to the respected column

Did small prototype as followed here but unable to save data.

<?php
ini_set('display_errors', '1');
ini_set('error_reporting', E_ALL);
use Magento\Framework\App\Bootstrap;
require __DIR__ . '/app/bootstrap.php';
$bootstrap = Bootstrap::create(BP, $_SERVER);
$objectManager = $bootstrap->getObjectManager();
$state = $objectManager->get('Magento\Framework\App\State');
$state->setAreaCode('frontend');

$sourceMaterial='24-MB01';
$productLink = $objectManager->create('Magento\Catalog\Api\Data\ProductLinkInterface')
    ->setSku($sourceMaterial)
    ->setLinkedProductSku('24-MB06')
    ->setLinkTitle("helloworld")
    ->setLinkType('required');
$linkData[] = $productLink;
$product = $objectManager->create('Magento\Catalog\Api\ProductRepositoryInterface')->get($sourceMaterial);
if($product) {
    $product->setProductLinks($linkData)->save();
}
?>

The recorded data is saving without link_title value not saving.

Answer 1

For create link_title column

Create InstallSchema.php :

app/code/RH/Helloworld/Setup/InstallSchema.php

<?php
namespace RH\Helloworld\Setup;

use Magento\Framework\Setup\InstallSchemaInterface;
use Magento\Framework\Setup\ModuleContextInterface;
use Magento\Framework\Setup\SchemaSetupInterface;

class InstallSchema implements InstallSchemaInterface {

/**
 * {@inheritdoc}
 * @SuppressWarnings(PHPMD.ExcessiveMethodLength)
 */
    public function install(SchemaSetupInterface $setup, ModuleContextInterface $context) {
        $installer = $setup;

        $installer->startSetup();

        $eavTable = $installer->getTable('catalog_product_link');

        $columns = [
            'link_title' => [
                'type' => \Magento\Framework\DB\Ddl\Table::TYPE_TEXT,
                'nullable' => true,
                'comment' => 'Link Title',
            ],

        ];

        $connection = $installer->getConnection();
        foreach ($columns as $name => $definition) {
            $connection->addColumn($eavTable, $name, $definition);
        }

        $installer->endSetup();
    }
}

For save record in custom column :

Inject this below code in your construct :

    protected $productFactory;

    public function __construct(
        ...
        \Magento\Catalog\Model\ProductFactory $productFactory
        ...
    ) {
        ....
        $this->productFactory = $productFactory;
        ....
    }

And then, use this below code in your function :

$product = $this->productFactory->create()->load(45); //Set your product id here
$link = $product->getLinkInstance()->load(1); //Set your link id here
$link->setLinkTitle('test'); //Set your link title value here
$link->save();

Don't forget to execute this below command :

php bin/magento s:up
php bin/magento s:s:d -f
php bin/magento c:c

Hope, It will helpful for you.

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Output :