Fatal error: Uncaught Error: Call to undefined function_name() in var/www

Question

Hi guys I am working on insert process after PDO connection using class. Everythings OK fot connection and displaying. But when I created new function in class and typed commands for insert process I've got this error line:

Fatal error: Uncaught Error: Call to undefined function db_connection_function() in /var/www/html/test/index.php:29 Stack trace: #0 /var/www/html/test/index.php(48): connection->add_member_to_table() #1 {main} thrown in /var/www/html/test/index.php on line 29

This function gives me error

public function add_member_to_table() {
    $this->query = db_connection_function()->prepare("INSERT INTO users(username, password) VALUES('onur', 'turali')");
    $this->query->execute();

    if($this->query == true) {
        echo "Member registered";
    } else {
        echo "Error";
    }
}

I tried $this-> connection_db_link.... I wanted try to type function name instead of connection_db_link(function name for connect to mysql) But this is useless I think. So How do I fix this problem?

My source codes:

<?php
    class connection{
        public $connection_db_link;
        public $db_host = "localhost";
        public $db_user = "root";
        public $db_pass = "Antalya07Ragnar";
        public $db_name = "test";

        public function db_connection_function(){
            try{
                $this -> connection_db_link = new PDO("mysql:host=$this->db_host;$this->db_name", $this->db_user, $this->db_pass);
                $this->connection_db_link->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
                return $this->connection_db_link;
            }catch(PDOException $e){
                echo "Error: ".$e->getMessage();
            }
        }

        public $query;

        public function add_member_to_table(){
            $this->query = db_connection_function()->prepare("INSERT INTO users(username, password) VALUES('onur', 'turali')");
            $this->query->execute();
            if($this->query == true){
                echo "Member registered";
            }else{
                echo "Error";
            }
        }

        public function display_connection(){
            if($this->connection_db_link == true){
                echo "Connection success";
            }
        }
    }

    $user = new connection;
    $user->db_connection_function();
    $user->display_connection();
    $user->add_member_to_table();
    ?>

its your method within your class, its $this->db_connection_function() and why not just create it in the constructor and just use it as a property instead — Kevin
When I need prepare for sql process, I always use function for connection. Because, I call the function before prepare command. But if connection function in another file, I use constructor. That is nto good way I know. But its, PDO connection using class, its really forced me. — user6728620
You shouldn't create a new connection every time you call the function. You should check if $this->connection_db_link is already set, and then return that variable instead of opening a new connection. — Barmar
Yes, logical. But should I call function or just PDO value for sql process after doing what you say? — user6728620

Rebecca Close Rebecca Close · Accepted Answer · 2016-09-21T23:21:32

Edit:

In the add_member_to_table() function, change db_connection_function() to $this->db_connection_function()

Before you attempt to use the db_connection_function() function, you should verify that you were successfully connected to the database.

Your PDO connection statement is missing dbname= and should look like this instead:

$this->connection_db_link = new PDO('mysql:host=$this->db_host;dbname=$this->db_name', $this->db_user, $this->db_pass);

After you're sure, the prepare statement works like this:

$stmt = $dbh->prepare("INSERT INTO users (username, password) VALUES (:username, :password)");
$stmt->bindParam(':username', $username);
$stmt->bindParam(':password', $password);

// insert one row
$name = 'onur';
$value = 'turali';
$stmt->execute();

Fatal error: Uncaught Error: Call to undefined function_name() in var/www

1 Answers