PHP + MYSQL 批量修改数据库 表名

$database = 'target';
mysql_connect('localhost','root','') or die('cannot connect');
mysql_select_db($database);
$query = mysql_query('show tables');

$prefix = 'target';
while($row = mysql_fetch_array($query)){
    $tableName = $row['Tables_in_'.$database];
    $string = explode('_',$tableName);
    if($string[0]!=$prefix){
        $string[0] = $prefix;
        $newTableName = implode('_', $string);
        mysql_query('rename table '.$tableName.' TO '.$newTableName);
    }
}