Database backup when clicking on a link

MySQL comes with a utility just for that, which is mysqldump . Locate this file on the machine and save its path. In PHP you can run this utility with exec , and save the backup to disk. Saving in a location accessible by webserver , just point the browser there. Example:

<?php
$caminhoDoMysqldump = "caminho/do/mysqldump/no/seu/servidor";
$usuario = "usuário do mysql";
$senha = "senha do mysql";
$banco = "seu_banco";
$saida = "/var/www/meuSite/arquivos/backup.sql"; // por exemplo

// Gera o backup e salva em disco
exec("$caminhoDoMysqldump --user=$usuario --password=$senha $banco > $saida");

// Redireciona o browser para o arquivo gerado
header('Location: http://www.meusite.com/arquivos/backup.sql');
exit;

You can also do the same without generating the file on disk, with passthru , which is very similar to exec but redirects the output to PHP. Example taken from a SOen response :

<?php

$DBUSER="user";
$DBPASSWD="password";
$DATABASE="user_db";

$filename = "backup-" . date("d-m-Y") . ".sql.gz";
$mime = "application/x-gzip";

header( "Content-Type: " . $mime );
header( 'Content-Disposition: attachment; filename="' . $filename . '"' );

$cmd = "mysqldump -u $DBUSER --password=$DBPASSWD $DATABASE | gzip --best";   

passthru( $cmd );

exit(0);
?>