InstallSchema.php

<?php
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */

namespace Magento\GoogleOptimizer\Setup;

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

/**
 * @codeCoverageIgnore
 */
class InstallSchema implements InstallSchemaInterface
{
    /**
     * {@inheritdoc}
     */
    public function install(SchemaSetupInterface $setup, ModuleContextInterface $context)
    {
        $installer = $setup;

        $installer->startSetup();

        /**
         * Create table 'googleoptimizer_code'
         */
        $table = $installer->getConnection()
            ->newTable($installer->getTable('googleoptimizer_code'))
            ->addColumn(
                'code_id',
                \Magento\Framework\DB\Ddl\Table::TYPE_INTEGER,
                null,
                ['identity' => true, 'unsigned' => true, 'nullable' => false, 'primary' => true],
                'Google experiment code id'
            )
            ->addColumn(
                'entity_id',
                \Magento\Framework\DB\Ddl\Table::TYPE_INTEGER,
                null,
                ['unsigned' => true, 'nullable' => false],
                'Optimized entity id product id or catalog id'
            )
            ->addColumn(
                'entity_type',
                \Magento\Framework\DB\Ddl\Table::TYPE_TEXT,
                50,
                [],
                'Optimized entity type'
            )
            ->addColumn(
                'store_id',
                \Magento\Framework\DB\Ddl\Table::TYPE_SMALLINT,
                null,
                ['unsigned' => true, 'nullable' => false],
                'Store id'
            )
            ->addColumn(
                'experiment_script',
                \Magento\Framework\DB\Ddl\Table::TYPE_TEXT,
                '64k',
                [],
                'Google experiment script'
            )
            ->addIndex(
                $installer->getIdxName(
                    'googleoptimizer_code',
                    ['store_id', 'entity_id', 'entity_type'],
                    \Magento\Framework\DB\Adapter\AdapterInterface::INDEX_TYPE_UNIQUE
                ),
                ['store_id', 'entity_id', 'entity_type'],
                ['type' => \Magento\Framework\DB\Adapter\AdapterInterface::INDEX_TYPE_UNIQUE]
            )
            ->addForeignKey(
                $installer->getFkName('googleoptimizer_code', 'store_id', 'store', 'store_id'),
                'store_id',
                $installer->getTable('store'),
                'store_id',
                \Magento\Framework\DB\Ddl\Table::ACTION_CASCADE
            )
            ->setComment('Google Experiment code');
        $installer->getConnection()->createTable($table);

        $installer->endSetup();

    }
}