Hey, yes it's possible to change the default type of your primary keys with a simple configuration

Open your config/databases.yml. It should looks like this :

 [yml]
# You can find more information about this file on the symfony website:
# http://www.symfony-project.org/reference/1_4/en/07-Databases

all:
  doctrine:
    class: sfDoctrineDatabase
    param:
      dsn:      mysql:host=localhost;dbname=.
      username: root
      password:

But Doctrine lets you customize some things. Now the file looks like :

 [yml]
# You can find more information about this file on the symfony website:
# http://www.symfony-project.org/reference/1_4/en/07-Databases

all:
  doctrine:
    class: sfDoctrineDatabase
    param:
      dsn:      mysql:host=localhost;dbname=.
      username: root
      password:
      attributes:
        default_identifier_options:
          type: integer
          length: 4
          unsigned: true

Nowyou can change the parameter, lets say an integer, and length: 5.

It's event possible to add any configuration that will be added automatically to your model.

Note: It's not possible to set autoincrement: false. True is forced by doctrine. Note: This behavior is true when no primary column is found in your schema.

Thanks to PhilG (#symfony-fr @ Freenode) for testing. Tested with symfony 1.4.1