php实现备份mysql数据库
作者: Knight
想在php后台管理直接能够备份数据库,于是想呀想,一直没有什么思路,一开始是考虑用php来访问服务器安装mysql的目录,比如 /usr/local/mysql/data目录,直接把下面对应的文件进行备份,但是出现了问题:
第一、运行php的是apche的用户,比如是nobody,那么它一般是没有权限访问/usr/local/mysql/data目录的
第二、就算能够访问,那么你如何能够把/usr/local/mysql/data目录下的文件拷贝出来呢?因为mysql在运行的时候是不运行访问的,那么nobody用户有权限停止mysql的服务,不可能!
越想越不对劲,没有办法,看能不能从php操作数据库入手,于是就去看了下phpMyadmin和Discuz!的代码,呵呵,于是偷抄了Discuz!的代码,形成了如下备份数据库的方法。(在这里感谢Discuz!的开发者)
备份数据库有两种方式,一种是只备份数据库的结构,一种把是结构和所有的数据都备份出来,当然是第二种方法好啦,不过我为了考虑可能的需求就都作啦。
/****** 备份数据库结构 ******/
/*
函数名称:table2sql()
函数功能:把表的结构转换成为SQL
函数参数:$table: 要进行提取的表名
返 回 值:返回提取后的结果,SQL集合
函数作者:heiyeluren
*/
function table2sql($table)
{
global $db;
$tabledump = "DROP TABLE IF EXISTS $table; ";
$createtable = $db->query("SHOW CREATE TABLE $table");
$create = $db->fetch_row($createtable);
$tabledump .= $create[1]."; ";
return $tabledump;
}
/****** 备份数据库结构和所有数据 ******/
/*
函数名称:data2sql()
函数功能:把表的结构和数据转换成为SQL
函数参数:$table: 要进行提取的表名
返 回 值:返回提取后的结果,SQL集合
函数作者:heiyeluren
*/
function data2sql($table)
{
global $db;
$tabledump = "DROP TABLE IF EXISTS $table; ";
$createtable = $db->query("SHOW CREATE TABLE $table");
$create = $db->fetch_row($createtable);
$tabledump .= $create[1]."; ";
$rows = $db->query("SELECT * FROM $table");
$numfields = $db->num_fields($rows);
$numrows = $db->num_rows($rows);
while ($row = $db->fetch_row($rows))
{
$comma = "";
$tabledump .= "INSERT INTO $table VALUES(";
for($i = 0; $i {
$tabledump .= $comma."".mysql_escape_string($row[$i])."";
$comma = ",";
}
$tabledump .= "); ";
}
$tabledump .= " ";
return $tabledump;
}
/****** 具体实现操作 ******/
好,我们既然把代码都写出来了,那么我们如何在具体的程序种去实现备份呢,我们看下面的代码。
/* 备份数据库 */
// 注意:我们一下的数据库操作采用了phplib的DB类
// 定义要保存的数据表、前缀、保存到何处
$tables = array(us_sort, us_download, us_article, us_guestbook); //定义要保存的数据表,一个数组
$prefix = us_; // 要保存的.sql文件的前缀
$saveto = server; // 要保存到什么地方,是本地还是服务器上,默认是服务器
$back_mode = all; // 要保存的方式,是全部备份还是只保存数据库结构
$admin = heiyeluren; //管理员名称
$admin_email = heiyeluren@163.com; // 管理员邮箱
// 定义数据保存的文件名
$local_filename = $prefix.date(Ymd_His)..sql";
if (!$filename) { $filename = $db_backup_path . $prefix . date(Ymd_His_). create_check_code(4) . ".sql"; }
$filename = $prefix.date(Ymd_His). create_check_ code(6).".sql"; // 保存在服务器上的文件名
// 注意后面的create_check_code()函数,这是一个生成随机码的函数,详细可以参考:
// aspx">http://blog.csdn.net/heiyeshuwu/archive/2005/01/26/268446.aspx
// 获取数据库结构和数据内容
foreach($tables as $table)
{
if ($back_mode == all) { $sqldump .= data2sql($table); }
if ($back_mode == table) { $sqldump .= table2sql($table); }
}
// 如果数据内容不是空就开始保存
if(trim($sqldump))
{
// 写入开头信息
$sqldump =
"# -------------------------------------------------------- ".
"# 数据表备份 ".
"# ".
"# 服务器: $db->Host ".
"# 数据库:$db->Database ".
"# 备份编号: ". create_sess_id() ." ". // 这里有一个生成session id的函数
"# 备份时间: ".time_to_date(,6)." ". // 这里就是获取当前时间的函数
"# ".
"# 管理员:$admin ($admin_email) ". // 管理员的用户名和邮箱地址
"# $copyright ".
"# -------------------------------------------------------- ".
$sqldump;
// 保存到本地
if($saveto == "local")
{
ob_end_clean();
header(Content-Encoding: none);
header(Content-Type: .(strpos($HTTP_SERVER_VARS[HTTP_USER_AGENT], MSIE) ? application/octetstream : application/octet-stream));
header(Content-Disposition: .(strpos($HTTP_SERVER_VARS[HTTP_USER_AGENT], MSIE) ? inline; : attachment; ).filename=".$local_filename);
header(Content-Length: .strlen($sqldump));
header(Pragma: no-cache);
header(Expires: 0);
echo $sqldump;
}
// 保存到本地结束
// 保存在服务器
if($saveto == "server")
{
if($filename != "")
{
@$fp = fopen($filename, "w+");
if ($fp)
{
@flock($fp, 3);
if(@!fwrite($fp, $sqldump))
{
@fclose($fp);
exit_msg("数据文件无法保存到服务器,请检查目录属性你是否有写的权限。");
}
else
{
exit_msg("数据成功备份至服务器 $filename 中。");
}
}
else
{
exit_msg("无法打开你指定的目录". $filename .",请确定该目录是否存在,或者是否有相应权限");
}
}
else
{
exit_msg("您没有输入备份文件名,请返回修改。");
}
}
// 保存到服务器结束
}
else
{
exit_msg("数据表没有任何内容");
}
/* 备份数据库结束 */
呵呵,基本上这样就结束了,然后涉及到的一个问题是如何把数据恢复到数据库中,我想这个是不复杂的,但是最好能够满足有从客户端和从服务器恢复数据的功能。

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