简单的mysql数据库备份程序

<?php    
$host="localhost";       
$user="root";    
$password="123456";      
$dbname="nbs";    
mysql_connect($host,$user,$password);       
mysql_select_db($dbname);     
$mysql= "set charset utf8;\r\n";         
$q1=mysql_query("show tables");         
while($t=mysql_fetch_array($q1)){    
    $table=$t[0];    
    $q2=mysql_query("show create table `$table`");         
    $sql=mysql_fetch_array($q2);     
    $mysql.=$sql['Create Table'].";\r\n\r\n";     
   
    $q3=mysql_query("select * from `$table`");    
    while($data=mysql_fetch_assoc($q3)){    
        $keys=array_keys($data);    
        $keys=array_map('addslashes',$keys);    
        $keys=join('`,`',$keys);       
        $keys="`".$keys."`";      
        $vals=array_values($data);     
        $vals=array_map('addslashes',$vals);      
        $vals=join("','",$vals);     
        $vals="'".$vals."'";    
        $mysql.="insert into `$table`($keys) values($vals);\r\n";    
    }    
    $mysql.="\r\n";                 
}    
$filename=date('Ymj').".sql";       
$fp = fopen($filename,'w');       
fputs($fp,$mysql);         
fclose($fp);         
echo "<br><center>数据备份成功,生成备份文件".$filename."</center>";           
?>