ORM piece of mind 4

---
structure:
    namespace: Acme\FooBundle\Entity
    tables:
        user:
            columns:
                userID:
                    type: int
                    unsigned: true
                    auto_increment: true
                    index:
                        primary:
                            type: primary
                groupID:
                    type: int
                    unsigned: true
                    null: true
                    default: null
                    index:
                        groupID:
                          type: index