PHP OOPs Concept:

Question

I am new to PHP. I have some doubts regarding PHP constructor. I have used 2 classes. One class contains constructor, Another class has insertion function. So I want to use the variable declared under constructor in order to write the insert query using mysqli. But I don't know how to access it. Can anyone pls help me with this one.

OOPDB.php
                <?php
            class Connection
            {
                //public $conn;
            public function __construct()
            {   
                $conn=mysqli_connect("localhost","root","Hatheem06","Emp");
                if(!$conn)
                    {
                        echo "DB not connected";
                    }
                else
                    {
                        echo "DB connected Successfully"."<br>";
                    }
            }
?>
FormDB.php
                <?php
            include ("OOPDB.php");
            $obj=new Connection();

            class User
            {
                public function insertion($name,$Uname,$Pswrd,$Age,$Email)

                {   
                    /*$sql=$conn->query("INSERT INTO Employee(Name,Username,Password,Age,Email)VALUES('$name','$Uname','$Pswrd','$Age','$Email')");
                    return $sql;*/
                    $ret=mysqli_query($conn,"insert into Employee(Name,Username,Password,Age,Email) values('$name','$Uname','$Pswrd','$Age','Email')");
                    return $ret;

                }
            }
            $Object=new User();


            if (isset($_POST['submit']))
                {       
                    $name=$_POST['Name'];
                    $Uname=$_POST['UName'];
                    $Pswrd=$_POST['pswd'];
                    $Age=$_POST['Age'];
                    $Email=$_POST['Email'];
                    $result=$Object->insertion($name,$Uname,$Pswrd,$Age,$Email);
                    if($result)
                    {
                    echo "Registration Successful";
                    }
                    else
                    {
                        echo "Not registered";
                    }

                }


            ?>
            <html>
                <head><h1 align="center">Employee Details</h1>

                    <title> Employee </title>
                        <link rel="stylesheet" type="text/css" href="Style.css">
                </head>
                <body>
                <div class="dtabb">
                    <form name="name" method="POST">
                        <table class="Etab">
                            <tr><td>Enter Your Name</td>
                                <td><input type="text" name="Name" ></td>
                            </tr>
                            <tr>
                                <td>Enter User Name</td>
                                <td><input type="text" name="UName" ></td>
                            </tr>
                            <tr>
                                <td>Enter password</td>
                                <td><input type="password" name="pswd"></td>
                            </tr>
                            <tr>
                                <td>Enter Your Age</td>
                                <td><input type="text" name="Age" ></td>
                            </tr>
                            <tr>
                                <td>Enter Mail ID of the Employee</td>
                                <td><input type="text" name="Email" ></td>
                            </tr>
                            <tr>
                                <td colspan="2"><center><input type="submit" name="submit" value="submit"/></center>
                                </td>
                            </tr>
                        </table>
                    </form>
                    </div>
                    </body>
                    </html>

Welcome to SO. Please read: [How to create a Minimal, Complete, and Verifiable example](http://stackoverflow.com/help/mcve) and also [How do I ask a good question?](http://stackoverflow.com/help/how-to-ask) — M. Eriksson, Jan 26 '17 at 15:22
can you give us your address (I'm kidding) so we can knock on your door, let us in so we can stand next to you in order to see your code? *sigh* — Funk Forty Niner, Jan 26 '17 at 15:22
*"But I don't know how to access it."* - You're not the only one ;-) — Funk Forty Niner, Jan 26 '17 at 15:24
and we'll be back after this message from our sponsor....... *"bye"* — Funk Forty Niner, Jan 26 '17 at 15:25
I have added my code, please have a look at it. I know there may be some errors, because i am new to PHP. — jasheema jasmin, Jan 26 '17 at 15:31
OK So where do you think $conn is hiding. Before getting into classes maybe you should start by understand variable scope http://php.net/manual/en/language.variables.scope.php — RiggsFolly, Jan 26 '17 at 15:32
@RiggsFolly They posted their code "after the fact" in order to avoid this duplicate I'll bet [Reference: What is variable scope, which variables are accessible from where and what are “undefined variable” errors?](http://stackoverflow.com/questions/16959576/reference-what-is-variable-scope-which-variables-are-accessible-from-where-and) — Funk Forty Niner, Jan 26 '17 at 15:34
Possible duplicate of [Reference: What is variable scope, which variables are accessible from where and what are “undefined variable” errors?](http://stackoverflow.com/questions/16959576/reference-what-is-variable-scope-which-variables-are-accessible-from-where-and) — Funk Forty Niner, Jan 26 '17 at 15:34
I knw it cannot be accessed anywhere except in that function. It has only local scope — jasheema jasmin, Jan 26 '17 at 15:35
Still I am searching how to access it. I tried using "GLOBAL" keyword also but not getting any output — jasheema jasmin, Jan 26 '17 at 15:37
Never use globals in classes it destroys the encapsulation that is the reason for using classes — RiggsFolly, Jan 26 '17 at 15:38
If I pass $conn as parameter to insertion function, Will it work? — jasheema jasmin, Jan 26 '17 at 15:56
Possible duplicate of [Reference: What is variable scope, which variables are accessible from where and what are "undefined variable" errors?](http://stackoverflow.com/questions/16959576/reference-what-is-variable-scope-which-variables-are-accessible-from-where-and) — Gabriel Rainha, Jan 26 '17 at 16:11

RiggsFolly · Answer 1 · 2017-01-26T16:01:24.930

I would suggest a static method in the Connection class that returns the connection handle. And thats all that need to be in that class

The in classes that need to connect call the getCOnn() method and store the connection returned as a property of themselves.

You also shoudl start using parameterised and bound queries, to protect yourself from SQL Injection.

OOPDB.php

<?php
class Connection
{
    private $conn = NULL;

    public static function getConn {  
        if (self::conn !== NULL) {
            return self::conn;
        }

        $conn=mysqli_connect("localhost","root","Hatheem06","Emp");

        if (!$conn) {
            echo "Error: Unable to connect to MySQL." . PHP_EOL;
            echo "Debugging errno: " . mysqli_connect_errno() . PHP_EOL;
            echo "Debugging error: " . mysqli_connect_error() . PHP_EOL;
            exit;
        } else {
            self::conn = $conn;
            return $conn;
        }
    }
}
?>

FormDB.php

<?php
include ("OOPDB.php");

class User
{
    private $conn;

    public function __construct() {
        $this->conn = Connection::getConn();
    }

    public function insertion($name,$Uname,$Pswrd,$Age,$Email) {   
        $sql = "insert into Employee
                        (Name,Username,Password,Age,Email) 
                values(?,?,?,?,?)");

        $stmt = $this->conn->prepare($sql);
        if ( ! $stmt ) {
            echo $stmt->error;
            return false;
        }
        $stmt->bind_param('sssis', $name,
                                    $Uname,
                                    $Pswrd,
                                    $Age,
                                    $Email
                            );
        $result = $stmt->execute();
        if ( ! $result ) {
            echo $stmt->error;
            return false;
        }
        return true;
    }
}        


$Object=new User();


if (isset($_POST['submit'])) {       
    $name=$_POST['Name'];
    $Uname=$_POST['UName'];
    $Pswrd=$_POST['pswd'];
    $Age=$_POST['Age'];
    $Email=$_POST['Email'];

    $result=$Object->insertion($name,$Uname,$Pswrd,$Age,$Email);
    if($result) {
        echo "Registration Successful";
    } else {
        echo "Not registered";
    }
}
?>

Thank u so much :-) Riggs. Is thr any other way without using static? — jasheema jasmin, Jan 26 '17 at 16:09

PHP OOPs Concept:

1 Answers1