How to Enable the Underscore Naming Strategy for Doctrine ORM in Symfony http://elnur.pro/how-to-enable-the-underscore-naming-strategy-for-doctrine-orm-in-symfony/

config.yml

doctrine:
    orm:
        naming_strategy: doctrine.orm.naming_strategy.underscore

schema.sql

CREATE TABLE super_user
(
    first_name varchar,
    last_name varchar
);

SuperUser.php

<?php

class SuperUser
{
    private $firstName;
    private $lastName;
}

SuperUser2.php

<?php

use Doctrine\ORM\Mapping\Table;
use Doctrine\ORM\Mapping\Column;

/**
 * @Table("super_user")
 */
class SuperUser
{
    /**
     * @Column("first_name")
     */
    private $firstName;

    /**
     * @Column("last_name")
     */
    private $lastName;
}