<?php

/**
 * @file
 * Install, update and uninstall functions for the Entity Reference
 * module.
 */

/**
 * Implements hook_field_schema().
 */
function entity_reference_field_schema($field) {
  $schema = array(
    'columns' => array(
      'target_id' => array(
        'description' => 'The ID of the target entity.',
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
      ),
      'revision_id' => array(
        'description' => 'The revision ID of the target entity.',
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => FALSE,
      ),
    ),
    'indexes' => array(
      'target_id' => array('target_id'),
    ),
    'foreign keys' => array(),
  );

  // Create a foreign key to the target entity type base type.
  // @todo It's still not safe to call entity_get_info() in here.
  // see http://drupal.org/node/1847582
  //  $entity_type = $field['settings']['target_type'];
  //  $entity_info = entity_get_info($entity_type);
  //
  //  $base_table = $entity_info['base_table'];
  //  $id_column = $entity_info['entity_keys']['id'];
  //
  //  $schema['foreign keys'][$base_table] = array(
  //    'table' => $base_table,
  //    'columns' => array('target_id' => $id_column),
  //  );

  return $schema;
}