4. Generating Migrations

If you are using the Doctrine 2 ORM you can easily generate a migration class by modifying your mapping information and running the diff task to compare it to your current database schema.

If you are using the sandbox you can modify the provided yaml/Entities.User.dcm.yml and add a new column:

Entities\User:
  # ...
  fields:
    # ...
    test:
      type: string
      length: 255
  # ...

Be sure that you add the property to the Entities/User.php file:

namespace Entities;

/** @Entity @Table(name="users") */
class User
{
    /**
     * @var string $test
     */
    private $test;

    // ...
}

Now if you run the diff task you will get a nicely generated migration with the changes required to update your database!

$ ./doctrine migrations:diff
Generated new migration class to "/path/to/migrations/DoctrineMigrations/Version20100416130459.php" from schema differences.

The migration class that is generated contains the SQL statements required to update your database:

namespace DoctrineMigrations;

use Doctrine\DBAL\Migrations\AbstractMigration,
    Doctrine\DBAL\Schema\Schema;

class Version20100416130459 extends AbstractMigration
{
    public function up(Schema $schema)
    {
        $this->addSql('ALTER TABLE users ADD test VARCHAR(255) NOT NULL');
    }

    public function down(Schema $schema)
    {
        $this->addSql('ALTER TABLE users DROP test');
    }
}

The SQL generated here is the exact same SQL that would be executed if you were using the orm:schema-tool task and the –update option. This just allows you to capture that SQL and maybe tweak it or add to it and trigger the deployment later across multiple database servers.