php备份mysql数据库

<?php   /*程序功能：mysql数据库备份功能*/ini_set('max_execution_time','0');ini_set('memory_limit','1024M');//加上这两行,可以备份大数据,昨晚测了一下公司的一个600M的表,很快就可以备份成功$code_type = 'gbk';header("Content-type:text/html;charset=$code_type");header("Content-disposition:   filename=backup.sql");//所保存的文件名   header("Content-type:   application/octetstream");   header("Pragma:   no-cache");   header("Expires:   0");   $conn   =   mysql_connect("localhost","root","root");   $db   =   mysql_select_db($dbname,$conn);   mysql_query("set names $code_type");$dbname="test";//数据库名$flag  = '1';//1:全部备份,2:只备份表结构,3:只备份数据echo back_database($dbname,$conn,$flag);//备份数据库//开始备份function back_database($dbname,$conn,$flag='1'){$crlf="\r\n";$str = '';$now = date('Y年m月d日H点i分s秒',time());$str .=   "$crlf--$crlf-- 数据库: `$dbname`$crlf--$crlf-- 导出日期: `$now`$crlf--$crlf";$str .=   "$crlf--$crlf-- 作者: ****$crlf--$crlf-- QQ: 1019822077$crlf--$crlf";$str .=   "-- blog: http://hi.baidu.com/woaidelphi/blog$crlf--$crlf";$str .=   "SET SQL_MODE=\"NO_AUTO_VALUE_ON_ZERO\";$crlf";$tables       =   mysql_list_tables($dbname,$conn);   $num_tables   =   mysql_numrows($tables);//表的总数 $i   =   0;while($i<$num_tables){//循环所有的表     $table =   mysql_tablename($tables,$i);   //备份表结构if($flag=='1' or $flag=='2'){$query =   mysql_query("SHOW CREATE TABLE $table");$row   =   mysql_fetch_row($query);$str .=  "-- --------------------------------------------------------$crlf$crlf";$str .=  "--$crlf-- 表的结构 `$table` $crlf--$crlf";$str .=  $row[1].";$crlf--$crlf";}//备份表内容 if($flag=='1' or $flag=='3'){$str .= "--$crlf-- 导出表中的数据 `$table` $crlf--$crlf";$str .=  get_table_content($dbname,$table);$str .= "$crlf$crlf";}$i++;   }return $str;}//得到表中的记录sql   function   get_table_content($dbname,$table){   $crlf            =   "\r\n";$schema_create   =   "";   $temp            =   "";   $result          =   mysql_db_query($dbname,"SELECT   *   FROM   $table");   $i               =   0;   while($row   =   mysql_fetch_row($result)){   $schema_insert   =   "INSERT   INTO   $table   VALUES   (";   for($j=0;   $j<mysql_num_fields($result);$j++){   if(!isset($row[$j]))   $schema_insert   .=   "   NULL,";   elseif($row[$j]   !=   "")   $schema_insert   .=   "   '".addslashes($row[$j])."',";   else   $schema_insert   .=   "   '',";   }   $schema_insert   =   ereg_replace(",$",   "",   $schema_insert);   $schema_insert   .=   ");$crlf";   $temp   =   $temp.$schema_insert   ;   $i++;   }   return   $temp;   }