PHP implements exporting MySQL database into .sql file instance (simulated with PHPMyadmin export function)

<?php

 header("Content-type:text/html;charset=utf-8");

//Configuration information
 $cfg_dbhost = 'localhost';
 $cfg_dbname = 'ftdm';
 $cfg_dbuser = 'root';
 $cfg_dbpwd = 'root';
 $cfg_db_language = 'utf8';
 $to_file_name = "";
// END configuration

//Link database
 $link = mysql_connect($cfg_dbhost,$cfg_dbuser,$cfg_dbpwd);
 mysql_select_db($cfg_dbname);
//Select encoding
 mysql_query("set names ".$cfg_db_language);
//What tables are there in the database
 $tables = mysql_list_tables($cfg_dbname);
//Record these tables to an array
 $tabList = array();
 while($row = mysql_fetch_row($tables)){
  $tabList[] = $row[0];
 }

echo "In operation, please wait patiently...<br/>";
 $info = "-- ----------------------------\r\n";
$info .= "-- Date: ".date("Y-m-d H:i:s",time())."\r\n";
$info .= "-- It is only used for testing and learning, this program is not suitable for processing too much data\r\n";
 $info .= "-- ----------------------------\r\n\r\n";
 file_put_contents($to_file_name,$info,FILE_APPEND);

//Export the table structure of each table to the file
 foreach($tabList as $val){
  $sql = "show create table ".$val;
  $res = mysql_query($sql,$link);
  $row = mysql_fetch_array($res);
  $info = "-- ----------------------------\r\n";
  $info .= "-- Table structure for `".$val."`\r\n";
  $info .= "-- ----------------------------\r\n";
  $info .= "DROP TABLE IF EXISTS `".$val."`;\r\n";
  $sqlStr = $info.$row[1].";\r\n\r\n";
//Add to file
  file_put_contents($to_file_name,$sqlStr,FILE_APPEND);
//Release resources
  mysql_free_result($res);
 }

//Export the data of each table to a file
 foreach($tabList as $val){
  $sql = "select * from ".$val;
  $res = mysql_query($sql,$link);
//If there is no data in the table, continue to the next table
  if(mysql_num_rows($res)<1) continue;
  //
  $info = "-- ----------------------------\r\n";
  $info .= "-- Records for `".$val."`\r\n";
  $info .= "-- ----------------------------\r\n";
  file_put_contents($to_file_name,$info,FILE_APPEND);
//Read data
  while($row = mysql_fetch_row($res)){
   $sqlStr = "INSERT INTO `".$val."` VALUES (";
   foreach($row as $zd){
    $sqlStr .= "'".$zd."', ";
   }
// Remove the last comma and space
   $sqlStr = substr($sqlStr,0,strlen($sqlStr)-2);
   $sqlStr .= ");\r\n";
   file_put_contents($to_file_name,$sqlStr,FILE_APPEND);
  }
//Release resources
  mysql_free_result($res);
  file_put_contents($to_file_name,"\r\n",FILE_APPEND);
 }

 echo "OK!";

?>