由网上搜到，有更改。

文件名：db_backup.php

源代码如下：
复制代码 代码如下:
<?php
ini_set("max_execution_time", "180");//避免数据量过大，导出不全的情况出现。

/*

程序功能：mysql数据库备份功能
作者：唐小刚
说明：
本程序主要是从mysqladmin中提取出来，并作出一定的调整，希望对大家在用php编程时备份数据有一定帮助.
如果不要备份结构：请屏掉这句:echo get_table_structure($dbname, $table, $crlf).";$crlf$crlf";
如果不要备份内容：请屏掉这句:echo get_table_content($dbname, $table, $crlf);

修改者：何锦盛
修改时间：2009/11/7
修改内容：新增函数get_table_structure，注释掉了函数get_table_def，目的是获得更丰富的建表时的细节（如：ENGINE=InnoDB AUTO_INCREMENT=80 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci COMMENT='商品信息变更信息'）
*/

$host="";//数据库地址

$dbname="";//这里配置数据库名

$username="";//用户名

$passw="";//这里配置密码

$filename=date("Y-m-d_H-i-s")."-".$dbname.".sql";
header("Content-disposition:filename=".$filename);//所保存的文件名
header("Content-type:application/octetstream");
header("Pragma:no-cache");
header("Expires:0");

//备份数据
$i = 0;
$crlf="\r\n";
global $dbconn;
$dbconn = mysql_connect($host,$username,$passw]);//数据库主机，用户名，密码
$db = mysql_select_db($dbname,$dbconn);
mysql_query("SET NAMES 'utf8'");
$tables =mysql_list_tables($dbname,$dbconn);
$num_tables = @mysql_numrows($tables);
print "-- filename=".$filename;
while($i < $num_tables)
{
$table=mysql_tablename($tables,$i);
print $crlf;
echo get_table_structure($dbname, $table, $crlf).";$crlf$crlf";
//echo get_table_def($dbname, $table, $crlf).";$crlf$crlf";
echo get_table_content($dbname, $table, $crlf);
$i++;
}

/*新增的获得详细表结构*/
function get_table_structure($db,$table,$crlf)
{
global $drop;

$schema_create = "";
if(!empty($drop)){ $schema_create .= "DROP TABLE IF EXISTS `$table`;$crlf";}
$result =mysql_db_query($db, "SHOW CREATE TABLE $table");
$row=mysql_fetch_array($result);
$schema_create .= $crlf."-- ".$row[0].$crlf;
$schema_create .= $row[1].$crlf;
Return $schema_create;
}

/*
//原来别人的取得数据库结构，但不完整
function get_table_def($db,$table,$crlf)
{
global $drop;

$schema_create = "";
if(!empty($drop))
$schema_create .= "DROP TABLE IF EXISTS `$table`;$crlf";

$schema_create .= "CREATE TABLE `$table` ($crlf";
$result = mysql_db_query($db, "SHOW full FIELDS FROM $table");
while($row = mysql_fetch_array($result))
{
$schema_create .= " `$row[Field]` $row[Type]";

if(isset($row["Default"]) && (!empty($row["Default"]) || $row["Default"] == "0"))
$schema_create .= " DEFAULT '$row[Default]'";
if($row["Null"] != "YES")
$schema_create .= " NOT NULL";
if($row["Extra"] != "")
$schema_create .= " $row[Extra]";
if($row["Comment"] != "")
$schema_create .= " Comment '$row[Comment]'";
$schema_create .= ",$crlf";
}
$schema_create = ereg_replace(",".$crlf."$", "", $schema_create);
$result = mysql_db_query($db, "SHOW KEYS FROM $table");
while($row = mysql_fetch_array($result))
{
$kname=$row['Key_name'];
if(($kname != "PRIMARY") && ($row['Non_unique'] == 0))
$kname="UNIQUE|$kname";
if(!isset($index[$kname]))
$index[$kname] = array();
$index[$kname][] = $row['Column_name'];
}

while(list($x,$columns) = @each($index))
{
$schema_create .= ",$crlf";
if($x == "PRIMARY")
$schema_create .= " PRIMARY KEY (".implode($columns,", ") . ")";
elseif (substr($x,0,6) == "UNIQUE")
$schema_create .= " UNIQUE ".substr($x,7)." (" . implode($columns, ", ") . ")";
else
$schema_create .= " KEY $x (" . implode($columns, ", ") . ")";
}

$schema_create .= "$crlf)";
return (stripslashes($schema_create));
}
*/

//获得表内容
function get_table_content($db, $table, $crlf)
{
$schema_create = "";
$temp = "";
$result = mysql_db_query($db, "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;
}
?>