Doctrine 2.1 – datetime column default value

For default value CURRENT_TIMESTAMP:

     @ORM\Column(name="created_at", type="datetime", options={"default": "CURRENT_TIMESTAMP"})

Or for older Symfony versions:

     @ORM\Column(name="created_at", type="datetime", options={"default": 0})

Worked for me… However this works only with MySQL.