yii2/tests/data/console/migrate_create/add_columns_fk.php

<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

return <<<CODE
<?php

use yii\db\Migration;

/**
 * Handles adding columns to table `{table}`.
 * Has foreign keys to the tables:
 *
 * - `user`
 * - `product`
 * - `user_order`
 */
class {$class} extends Migration
{
    /**
     * @inheritdoc
     */
    public function up()
    {
        \$this->addColumn('{table}', 'user_id', \$this->integer());
        \$this->addColumn('{table}', 'product_id', \$this->integer()->unsigned()->notNull());
        \$this->addColumn('{table}', 'order_id', \$this->integer()->notNull());
        \$this->addColumn('{table}', 'created_at', \$this->dateTime()->notNull());

        // creates index for column `user_id`
        \$this->createIndex(
            'idx-{table}-user_id',
            '{table}',
            'user_id'
        );

        // add foreign key for table `user`
        \$this->addForeignKey(
            'fk-{table}-user_id',
            '{table}',
            'user_id',
            'user',
            'id',
            'CASCADE'
        );

        // creates index for column `product_id`
        \$this->createIndex(
            'idx-{table}-product_id',
            '{table}',
            'product_id'
        );

        // add foreign key for table `product`
        \$this->addForeignKey(
            'fk-{table}-product_id',
            '{table}',
            'product_id',
            'product',
            'id',
            'CASCADE'
        );

        // creates index for column `order_id`
        \$this->createIndex(
            'idx-{table}-order_id',
            '{table}',
            'order_id'
        );

        // add foreign key for table `user_order`
        \$this->addForeignKey(
            'fk-{table}-order_id',
            '{table}',
            'order_id',
            'user_order',
            'id',
            'CASCADE'
        );
    }

    /**
     * @inheritdoc
     */
    public function down()
    {
        // drops foreign key for table `user`
        \$this->dropForeignKey(
            'fk-{table}-user_id',
            '{table}'
        );

        // drops index for column `user_id`
        \$this->dropIndex(
            'idx-{table}-user_id',
            '{table}'
        );

        // drops foreign key for table `product`
        \$this->dropForeignKey(
            'fk-{table}-product_id',
            '{table}'
        );

        // drops index for column `product_id`
        \$this->dropIndex(
            'idx-{table}-product_id',
            '{table}'
        );

        // drops foreign key for table `user_order`
        \$this->dropForeignKey(
            'fk-{table}-order_id',
            '{table}'
        );

        // drops index for column `order_id`
        \$this->dropIndex(
            'idx-{table}-order_id',
            '{table}'
        );

        \$this->dropColumn('{table}', 'user_id');
        \$this->dropColumn('{table}', 'product_id');
        \$this->dropColumn('{table}', 'order_id');
        \$this->dropColumn('{table}', 'created_at');
    }
}

CODE;