请教用PHP备份MYSQL数据的做法

我们一般会直接用mysqldump来备份数据库（表），那请问用PHP备份MYSQL数据表如何做，特别是当MYSQL数据表非常大的情况。

backup_tables('localhost','username','password','blog');


function backup_tables($host,$user,$pass,$name,$tables = '*')
{

$link = mysql_connect($host,$user,$pass);
mysql_select_db($name,$link);

if($tables == '*')
{
$tables = array();
$result = mysql_query('SHOW TABLES');
while($row = mysql_fetch_row($result))
{
  $tables[] = $row[0];
}
}
else
{
$tables = is_array($tables) ? $tables : explode(',',$tables);
}

foreach($tables as $table)
{
$result = mysql_query('SELECT * FROM '.$table);
$num_fields = mysql_num_fields($result);

$return.= 'DROP TABLE '.$table.';';
$row2 = mysql_fetch_row(mysql_query('SHOW CREATE TABLE '.$table));
$return.= "\n\n".$row2[1].";\n\n";

for ($i = 0; $i < $num_fields; $i++) 
{
  while($row = mysql_fetch_row($result))
  {
    $return.= 'INSERT INTO '.$table.' VALUES(';
    for($j=0; $j<$num_fields; $j++) 
    {
      $row[$j] = addslashes($row[$j]);
      $row[$j] = ereg_replace("\n","\\n",$row[$j]);
      if (isset($row[$j])) { $return.= '"'.$row[$j].'"' ; } else { $return.= '""'; }
      if ($j<($num_fields-1)) { $return.= ','; }
    }
    $return.= ");\n";
  }
}
$return.="\n\n\n";
}

$handle = fopen('db-backup-'.time().'-'.(md5(implode(',',$tables))).'.sql','w+');
fwrite($handle,$return);
fclose($handle);
}

php代码：

$host="localhost";
$user="root";
$password="";
$dbname="dbname";

mysql_connect($host,$user,$password);
mysql_select_db($dbname);
$mysql= "set names utf8;";
mysql_query($mysql);
$q1=mysql_query("show tables");
while($t=mysql_fetch_array($q1)){
$table=$t[0];
$q2=mysql_query("show create table `$table`");
$sql=mysql_fetch_array($q2);
$mysql.=$sql['Create Table'].";\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);\n";
}
$mysql.="\n";
}
$filename=date('Ymj').".sql";
$fp = fopen($filename,'w');
fputs($fp,$mysql);
fclose($fp);
echo "数据备份成功,生成备份文件".$filename;

把表结构和数据每条都读出来然后写入文件

直接用mysqldump在服务器做一个脚本，然后写一个计划任务 即可