PHP导出数据库方法

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　　（1）定义一个db_dump函数如下：



<?PHP
function db_dump($host,$user,$pwd,$db) {
$mysqlconlink = mysql_connect($host,$user,$pwd , true);
if (!$mysqlconlink)
echo sprintf('No MySQL connection: %s',mysql_error())."<br/>";
mysql_set_charset( 'utf8', $mysqlconlink );
$mysqldblink = mysql_select_db($db,$mysqlconlink);
if (!$mysqldblink)
echo sprintf('No MySQL connection to database: %s',mysql_error())."<br/>";
$tabelstobackup=array();
$result=mysql_query("SHOW TABLES FROM `$db`");
if (!$result)
echo sprintf('Database error %1$s for query %2$s', mysql_error(), "SHOW TABLE STATUS FROM `$db`;")."<br/>";
while ($data = mysql_fetch_row($result)) {
$tabelstobackup[]=$data[0];
}
if (count($tabelstobackup)>0) {
$result=mysql_query("SHOW TABLE STATUS FROM `$db`");
if (!$result)
echo sprintf('Database error %1$s for query %2$s', mysql_error(), "SHOW TABLE STATUS FROM `$db`;")."<br/>";
while ($data = mysql_fetch_assoc($result)) {
$status[$data['Name']]=$data;
}
if ($file = fopen("$db.sql", 'wb')) {
fwrite($file, "-- ---------------------------------------------------------\n");
fwrite($file, "-- Database Name: $db\n");
fwrite($file, "-- ---------------------------------------------------------\n\n");
fwrite($file, "/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;\n");
fwrite($file, "/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;\n");
fwrite($file, "/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;\n");
fwrite($file, "/*!40101 SET NAMES '".mysql_client_encoding()."' */;\n");
fwrite($file, "/*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;\n");
fwrite($file, "/*!40103 SET TIME_ZONE='".mysql_result(mysql_query("SELECT @@time_zone"),0)."' */;\n");
fwrite($file, "/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;\n");
fwrite($file, "/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;\n");
fwrite($file, "/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;\n");
fwrite($file, "/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;\n\n");
foreach($tabelstobackup as $table) {
echo sprintf('Dump database table "%s"',$table)."<br/>";
need_free_memory(($status[$table]['Data_length']+$status[$table]['Index_length'])*3);
_db_dump_table($table,$status[$table],$file);
}
fwrite($file, "\n");
fwrite($file, "/*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;\n");
fwrite($file, "/*!40101 SET SQL_MODE=@OLD_SQL_MODE */;\n");
fwrite($file, "/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;\n");
fwrite($file, "/*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;\n");
fwrite($file, "/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;\n");
fwrite($file, "/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;\n");
fwrite($file, "/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;\n");
fwrite($file, "/*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;\n");
fclose($file);
echo 'Database dump done!'."<br/>";
} else {
echo 'Can not create database dump!'."<br/>";
}
} else {
echo 'No tables to dump'."<br/>";
}
}
function _db_dump_table($table,$status,$file) {
fwrite($file, "\n");
fwrite($file, "--\n");
fwrite($file, "-- Table structure for table $table\n");
fwrite($file, "--\n\n");
fwrite($file, "DROP TABLE IF EXISTS `" . $table .  "`;\n");
fwrite($file, "/*!40101 SET @saved_cs_client     = @@character_set_client */;\n");
fwrite($file, "/*!40101 SET character_set_client = '".mysql_client_encoding()."' */;\n");
$result=mysql_query("SHOW CREATE TABLE `".$table."`");
if (!$result) {
echo sprintf('Database error %1$s for query %2$s', mysql_error(), "SHOW CREATE TABLE `".$table."`")."<br/>";
return false;
}
$tablestruc=mysql_fetch_assoc($result);
fwrite($file, $tablestruc['Create Table'].";\n");
fwrite($file, "/*!40101 SET character_set_client = @saved_cs_client */;\n");
$result=mysql_query("SELECT * FROM `".$table."`");
if (!$result) {
echo sprintf('Database error %1$s for query %2$s', mysql_error(), "SELECT * FROM `".$table."`")."<br/>";
return false;
}
fwrite($file, "--\n");
fwrite($file, "-- Dumping data for table $table\n");
fwrite($file, "--\n\n");
if ($status['Engine']=='MyISAM')
fwrite($file, "/*!40000 ALTER TABLE `".$table."` DISABLE KEYS */;\n");
while ($data = mysql_fetch_assoc($result)) {
$keys = array();
$values = array();
foreach($data as $key => $value) {
if($value === NULL)
$value = "NULL";
elseif($value === "" or $value === false)
$value = "''";
elseif(!is_numeric($value))
$value = "'".mysql_real_escape_string($value)."'";
$values[] = $value;
}
fwrite($file, "INSERT INTO `".$table."` VALUES ( ".implode(", ",$values)." );\n");
}
if ($status['Engine']=='MyISAM')
fwrite($file, "/*!40000 ALTER TABLE ".$table." ENABLE KEYS */;\n");
}
function need_free_memory($memneed) {
if (!function_exists('memory_get_usage'))
return;
$needmemory=@memory_get_usage(true)+inbytes($memneed);
if ($needmemory>inbytes(ini_get('memory_limit'))) {
$newmemory=round($needmemory/1024/1024)+1 .'M';
if ($needmemory>=1073741824)
$newmemory=round($needmemory/1024/1024/1024) .'G';
if ($oldmem=@ini_set('memory_limit', $newmemory))
echo sprintf(__('Memory increased from %1$s to %2$s','backwpup'),$oldmem,@ini_get('memory_limit'))."<br/>";
else
echo sprintf(__('Can not increase memory limit is %1$s','backwpup'),@ini_get('memory_limit'))."<br/>";
}
}
function inbytes($value) {
$multi=strtoupper(substr(trim($value),-1));
$bytes=abs(intval(trim($value)));
if ($multi=='G')
$bytes=$bytes*1024*1024*1024;
if ($multi=='M')
$bytes=$bytes*1024*1024;
if ($multi=='K')
$bytes=$bytes*1024;
return $bytes;
}
?>
　　（2）使用方法：



db_dump('数据库服务器', '数据库用户名', '数据库密码', '数据库名');