connection with database with OOP mysqli extending class

Question

I know must coding part of mysql bt new at mysqli. I am not able to execute these insert query to the database. I have searched a lot but couldn\'t find simple suggestion, or ma

Answer 1

In both of your connect() and insertdata() methods, you're using local variable $mysqli, not the instance variable public $mysqli;. You should use $this->mysqli instead of $mysqli in your instance methods. So your connect() and insertdata() methods would be like this:

function connect(){
    $hostname = "localhost";
    $username = "root";
    $password = "";
    $database = "demodatabase";
    $this->mysqli = new mysqli($hostname, $username, $password, $database);
    /* check connection */
    if (mysqli_connect_errno()) {
        printf("Connect failed: %s\n", mysqli_connect_error());
        exit();
    }
    return true;            
}

and

function insertdata($a, $b){
    $insert_row = $this->mysqli->query("INSERT INTO tb_user (id, user, password, status) VALUES('','".$a."', '".$b."', '')");
    if($insert_row){
        print 'saved'; 
    }else{
        die('Error : ('. $this->mysqli->errno .') '. $this->mysqli->error);
    }
}

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Sidenote: Learn about prepared statement because right now your query is susceptible to SQL injection attack. Also see how you can prevent SQL injection in PHP.