/**
 * Implements hook_field_storage_delete_field().
 */
function {{ machine_name }}_field_storage_delete_field($field) {
  // Mark all data associated with the field for deletion.
  $field['deleted'] = 0;
  $table = _field_sql_storage_tablename($field);
  $revision_table = _field_sql_storage_revision_tablename($field);
  db_update($table)
    ->fields(array('deleted' => 1))
    ->execute();

  // Move the table to a unique name while the table contents are being deleted.
  $field['deleted'] = 1;
  $new_table = _field_sql_storage_tablename($field);
  $revision_new_table = _field_sql_storage_revision_tablename($field);
  db_rename_table($table, $new_table);
  db_rename_table($revision_table, $revision_new_table);
  drupal_get_schema(NULL, TRUE);
}
