function ctools_field_foreign_keys

Derive the foreign keys that a field provides.

Parameters

$field_name: The name of the field.

Return value

An array of foreign keys according to Schema API.

File

includes/fields.inc, line 339

Code

function ctools_field_foreign_keys($field_name) {
    $foreign_keys =& drupal_static(__FUNCTION__, array());
    if (!isset($foreign_keys[$field_name])) {
        $foreign_keys[$field_name] = array();
        $field = field_info_field($field_name);
        if (!empty($field['foreign keys'])) {
            $foreign_keys[$field_name] = $field['foreign keys'];
        }
        else {
            // Try to fetch foreign keys from schema, as not everything
            // stores foreign keys properly in the field info.
            $module = $field['module'];
            module_load_install($module);
            $schema = module_invoke($module, 'field_schema', $field);
            if (!empty($schema['foreign keys'])) {
                $foreign_keys[$field_name] = $schema['foreign keys'];
            }
        }
    }
    return $foreign_keys[$field_name];
}