php MYSQL data backup class_PHP tutorial

/*
*
*A simple backup data class
*author FC
*
*/
class backupData{
private $mysql_link;//Link identification
private $dbName;//Database name
private $dataDir; //Directory where the data is to be stored
private $tableNames;//Table name
public function __construct( $mysql_link){

$this->mysql_link = $mysql_link;
}

public function backupTables($dbName,$dataDir,$tableNames){//Start backup

$this->dbName = $dbName;
$this->dataDir = $dataDir;
$this->tableNames = $tableNames;
$tables=$this-> ;delarray($this->tableNames);
$sqls='';
foreach($tables as $tablename){
if($tablename==''){//The table does not exist When
continue;
}
//**********************The following is the first half of the SQL**** **********
//If the table exists, delete it first
$sqls .= "DROP TABLE IF EXISTS $tablename;n";
//Read the table structure
$rs = mysql_query("SHOW CREATE TABLE $tablename",$this->mysql_link);
$row=mysql_fetch_row($rs);
//Get the table structure to form SQL
$sqls .=$row['1'].";nn";
unset($rs);
unset($row);
//************ ************The following is the second half of the SQL**************
//Find all the data in the table
$ rs=mysql_query("select * from $tablename",$this->mysql_link);
//The number of fields in the table
$field=mysql_num_fields($rs);
//Form this SQL statement: "INSERT INTO `groups` VALUES('1499e0ca25988d','Director','','0');"
while($rows=mysql_fetch_row($rs)){
$comma=' ';//Comma
$sqls.="INSERT INTO `$tablename` VALUES(";
for($i=0;$i<$field;$i++){
$sqls.= $comma."'".$rows[$i]."'";
$comma=',';
}
$sqls.=");nnn";
}
}
$backfilepath=$this->dataDir.date("Ymdhis",time()).'.sql';
//Write file
$filehandle = fopen($backfilepath , "w");
fwrite($filehandle, $sqls);
fclose($filehandle);
}

private function delarray($array){//process incoming Incoming array
foreach($array as $tables){
if($tables=='*'){//All tables (when obtaining the table name, you cannot form an array in the usual way)
$newtables=mysql_list_tables($this->dbName,$this->mysql_link);
$tableList = array();
for ($i = 0; $i < mysql_numrows($newtables) ; $i++){
array_push($tableList,mysql_tablename($newtables, $i));
}
$tableList=$tableList;
}else{
$tableList=$array ;
break;
}
}
return $tableList;
}
}