Contructor,用于连接数据库(MYSQL)的析构函数

我正在使用构造函数连接到数据库，并使用析构函数断开连接。我想知道的是:从构造函数调用this是否更有效?那么析构函数呢?使用准备好的语句连接到数据库是安全的还是好的编码?

如何创建插入方法?

public function __construct($host, $username, $password, $dbname, $tablename="")
        {
            $this->host = $host;
            $this->username = $username;
            $this->password = $password;
            $this->dbname = $dbname;
            $this->tablename = $tablename;
            $this->con = mysqli_connect($host, $username, $password, $dbname); //connecting...
 if(mysqli_connect_errno($this->con))
    {
    echo "Failed to connect to MySQL: " . mysqli_connect_error();
    }
    else
    {
    echo "Connection Established<br>";
    } 
}
public function __destruct()
{
    if(mysqli_close($this->con))
    {
        echo "<br>Connection Terminated";
    } 
}