public static function splitKey($key)
    {
        if (strpos($key, self::FIELD_KEY_SEPARATOR) === false) {
            return null;
        }
        list($sub, $fieldId) = explode(self::FIELD_KEY_SEPARATOR, $key, 2);

        return array('sub' => $sub, 'gtf_id_field' => $fieldId);
    }
public static function splitKey($key)
    {
        if (strpos($key, self::FIELD_KEY_SEPARATOR) === false) {
            return null;
        }
        list($sub, $fieldId) = explode(self::FIELD_KEY_SEPARATOR, $key, 2);

        return array('sub' => $sub, 'gtf_id_field' => $fieldId);
    }
public static function splitKey ( $ key ) { if ( strpos ( $ key , self :: FIELD_KEY_SEPARATOR ) === false ) { return null ; } list ( $ sub , $ fieldId ) = explode ( self :: FIELD_KEY_SEPARATOR , $ key , 2 ) ; return array ( 'sub' => $ sub , 'gtf_id_field' => $ fieldId ) ; }
Split an external field key in component parts

@param string $sub
@param int $fieldId
@return array 'sub' => suIdb, 'gtf_id_field; => fieldId
Split an external field key in component parts