how to update a field schema I am trying to add a field (middle name) into the field_schema of the contrib addressfield module (I initially didn't want to hack it, but was unsucessful in adding a field in from my custom module.). The module has the following hook_field_schema()

function addressfield_field_schema() {
  $columns = array(
    'country' => array(
      'description' => 'Two letter ISO country code of this address.',
      'type' => 'varchar',
      'length' => 2,
      'not null' => FALSE,
      'default' => '',
    ),
    'administrative_area' => array(
      'description' => 'The administrative area of this address. (i.e. State/Province)',
      'type' => 'varchar',
      'length' => 255,
      'default' => '',
      'not null' => FALSE,
    ),
    'sub_administrative_area' => array(
      'description' => 'The sub administrative area of this address.',
      'type' => 'varchar',
      'length' => 255,
      'default' => '',
      'not null' => FALSE,
    ),
    'locality' => array(
      'description' => 'The locality of this address. (i.e. City)',
      'type' => 'varchar',
      'length' => 255,
      'default' => '',
      'not null' => FALSE,
    ),
    'dependent_locality' => array(
      'description' => 'The dependent locality of this address.',
      'type' => 'varchar',
      'length' => 255,
      'default' => '',
      'not null' => FALSE,
    ),
    'postal_code' => array(
      'description' => 'The postal code of this address.',
      'type' => 'varchar',
      'length' => 255,
      'default' => '',
      'not null' => FALSE,
    ),
    'thoroughfare' => array(
      'description' => 'The thoroughfare of this address. (i.e. Street address)',
      'type' => 'varchar',
      'length' => 255,
      'default' => '',
      'not null' => FALSE,
    ),
    'premise' => array(
      'description' => 'The premise of this address. (i.e. Apartment / Suite number)',
      'type' => 'varchar',
      'length' => 255,
      'default' => '',
      'not null' => FALSE,
    ),
    'sub_premise' => array(
      'description' => 'The sub_premise of this address.',
      'type' => 'varchar',
      'length' => 255,
      'default' => '',
      'not null' => FALSE,
    ),
    'organisation_name' => array(
      'description' => 'Contents of a primary OrganisationName element in the xNL XML.',
      'type' => 'varchar',
      'length' => 255,
      'not null' => FALSE,
      'default' => '',
    ),
    'name_line' => array(
      'description' => 'Contents of a primary NameLine element in the xNL XML.',
      'type' => 'varchar',
      'length' => 255,
      'not null' => FALSE,
      'default' => '',
    ),
    'first_name' => array(
      'description' => 'Contents of the FirstName element of a primary PersonName element in the xNL XML.',
      'type' => 'varchar',
      'length' => 255,
      'not null' => FALSE,
      'default' => '',
    ),
    'last_name' => array(
      'description' => 'Contents of the LastName element of a primary PersonName element in the xNL XML.',
      'type' => 'varchar',
      'length' => 255,
      'not null' => FALSE,
      'default' => '',
    ),
    'last_name' => array(
      'description' => 'Contents of the LastName element of a primary PersonName element in the xNL XML.',
      'type' => 'varchar',
      'length' => 255,
      'not null' => FALSE,
      'default' => '',
    ),
    'data' => array(
      'description' => 'Additional data for this address.',
      'type' => 'text',
      'size' => 'big',
      'not null' => FALSE,
      'serialize' => TRUE,
    ),
  );

  return array(
    'columns' => $columns,
    // TODO Add indexes.
  );
}

I found this post online for doing a field_schema update https://drupal.org/node/150215, but I don't know what the field name or table name is, its not listed in the file.
How can I do this?
My ultimate goal is to make a standalone plugin file to be used by addressfield, but I needed to update the schema first.
The field will be named whatever you named it when you added it. If you can't remember, go to the "Manage fields" UI page for the relevant entity type/bundle and you'll be able to find it there.

The table names will be based on that field name; if the field is called field_my_field then the two database tables are:


field_data_field_my_field
field_revision_field_my_field