DEV Community: Elijah Emmanuel

How can I avoid multiple deduction from stocks in my SQL db in php while loop?

Elijah Emmanuel — Fri, 12 Aug 2022 20:28:00 +0000

Please 🙏 guys, I have been having issues when I have alot of people trying to checkout after placing orders on my site.
I made use of while loop to ensure that the quantity ordered deducts from available quantity in my SQL database, but instead of deducting as planned, it deducts excess.
Here is my code below....
Am I doing it the wrong way?



<?php
//Database connection
include("db/config.php");

//Session to get user id
$user_id=$_SESSION['id'];
$statuss='added';

   $value2='';

    //Query to fetch last inserted invoice number and create a new invoice number 
    $query = "SELECT invoice_no from invoice order by invoice_no DESC LIMIT 1";
    $stmt = $conn->query($query);
    if(mysqli_num_rows($stmt) > 0) {
        if ($row = mysqli_fetch_assoc($stmt)) {
            $value2 = $row['invoice_no'];
            $value2 = substr($value2, 10, 13);//separating numeric part
            $value2 = $value2 + 1;//Incrementing numeric part
            $value2 = "ARW/19-20/" . sprintf('%03s', $value2);//concatenating incremented value
            $value = $value2; 
        }
    } 
    else {
        $value2 = "ARW/19-20/001";
        $value = $value2;
    }
    // echo $value;
if(isset($_POST['check_out'])){

   //Main code

//Get all input values
$name=mysqli_real_escape_string($conn,$_POST['name']);
    $phone=mysqli_real_escape_string($conn,$_POST['phone']);
    $address=mysqli_real_escape_string($conn,$_POST['address']);
    $payment_method=mysqli_real_escape_string($conn,$_POST['payment_mtd']);




        $added='added';
//Get session name     $user_name=$_SESSION['name'];

//Query to update order operation table
        $sql="UPDATE order_operation SET name='$name', user_name='$user_name', phone='$phone', address='$address',payment='$payment_method' WHERE user_id=$user_id AND status='$added'";   
        if($conn->query($sql) === TRUE){
//Declare variables       
$before='added';
$status='completed';

//Update order operation with created invoice number

$sql="UPDATE order_operation SET status=?, invoice_no=? WHERE user_id='$user_id' AND status='$before'";
            $stmt=$conn->prepare($sql); 
            $stmt->bind_param('ss',$status,$value);
            if($stmt->execute()){
                $sql="INSERT INTO invoice(invoice_no,user_id) VALUES('$value','$user_id')";
                $conn->query($sql);
                    //Deduct from stock
                    $sql = "SELECT * FROM `order_operation` WHERE invoice_no='$value'";
                    $sql_run = mysqli_query($conn, $sql);

                    while ($row = mysqli_fetch_array($sql_run)) {
 //Deduct from stock since the order id's meet the requirements                                         $deduct=$row['stock_quantity'] - $row['quantity'];
                            $stock_id=$row['stock_id'];
                           $connector= "UPDATE stocks SET quantity =  '$deduct' WHERE id = $stock_id" ;
                           if($conn->query($connector) === TRUE){


                                $_SESSION['customer_name']=$name;   
                                $_SESSION['phone']=$phone;
                                $_SESSION['address']=$address;
                                $_SESSION['payment']=$payment_method;
                                $_SESSION['invoice_no']=$row['invoice_no'];
                                header('location:order_invoice.php');

                           }else{
                            echo $conn->error;
                           }



                        }
                        //End of deduct from stock

                    $conn->close();

                 }else{
                    die($conn->error);

                 }
             }else{

                 die($conn->error);

             }


               $stmt->close();
               $conn->close();

}


?>

Please How can I convert the following object oriented PDO fetch_assoc to MYsqli Format below.

Elijah Emmanuel — Thu, 02 Dec 2021 14:00:46 +0000

Hi Great Developers, I am having a difficult time fetching data from my database using object PHP as below.

So I have two pages,

One for fetching data from my DB and returning it
And another for displaying the data from my database fetched from the first page.

As Below
The code below is a function written with PDO

First page.

function get_messages() 
{
//fetch data from db

$sql="SELECT user_name, msg, timestamp FROM message_chat";

//prepare and execute. 
$stmt=$conn->prepare($sql);

$stmt->execute() ;

//Now this is the line thats making things complicated. 

return $stmt->fetchAll(PDO::FETCH_ASSOC) ;
}

Now, the second page is meant to return the generated data's from the above code, but its not happening.
Please how can I convert the above PDO fetch_assoc statement to mysqli so I can use it in my project.

HOW TO RETURN PDO fetch_assoc FROM PDO TO MYsqli

Elijah Emmanuel — Thu, 25 Nov 2021 01:30:50 +0000

please how can I convert the following the following code from PDO to MYsqli in order to return it.

HOW CAN I LIMIT THE MAXIMUM FILE UPLOAD LIMIT PER USER IN PHP.

Elijah Emmanuel — Tue, 02 Nov 2021 03:09:35 +0000

Hello guys,
i have been trying for some days now to make it possible for each user in my website to only upload a maximum of 4 images and when ever he/she wants to upload the fifth image an error massage would be echoed telling the user that The maximum image to be uploaded have reached and cannot exceed 4 image

Below is the sample of the code on form submit

if (isset($_POST['upload'])) { 
// if upload button on the form is clicked

// name of the uploaded file
$filename = $_FILES['photo']['name'];

//location
$destination = '../images/business.cover/' . $filename;

// get the file extension
$extension = pathinfo($filename, PATHINFO_EXTENSION);

// the physical file on a temporary uploads directory on the server
$file = $_FILES['photo']['tmp_name'];
$size = $_FILES['photo']['size'];

// get id
$id=$_GET['id'];

//check is form is empty
if(empty($_POST['photo'])){
    $cover_msg= "<div class='alert alert-danger'>Empty cover phto field</div>";
}

//check file extension and maximum file size
if (!in_array($extension, ['jpg', 'gif', 'jpeg','png'])) {
    $cover_msg= "<div class='alert alert-danger'>You file extension must be .jpg .jpeg .gif .png</div>";
} elseif ($_FILES['photo']['size'] > 50000000) { // file shouldn't be larger than 1Megabyte
    $cover_msg= "<div class='alert alert-danger'>File too large!</div>";

} else {


// move the uploaded (temporary) file to the specified destination
    if (move_uploaded_file($file, $destination);) {

$sql = "INSERT INTO business(image) VALUES('$filename') WHERE id=$id";  

$cover_msg="<div class='alert alert-success'>Information uploaded Successfully</div>";
if (mysqli_query($conn, $sql)) {
} else {
die( "Failed to upload file".$conn->error);
}

}

}
}

PLEASE HELP, ANYONE

How can i create a chat app with json on php

Elijah Emmanuel — Thu, 07 Oct 2021 15:35:56 +0000

Please how can I create a chatting app with php, I have tried all means but but don't know what am missing,
Below is the cade for the database connection and json code used to convert it

<?php
$localhost="localhost";
$user="root";
$password="";
$db='chat';
$conn=new mysqli($localhost,$user,$password,$db);

if ($conn->connect_error) {
die("unable to connect to server");
}

$result=array();

$message= isset($_POST['message']) ? $_POST['message']:null;
$from=isset($_POST['from']) ? $_POST['from']:null;

if(!empty($message) && !empty($from)){
$sql="INSERT INTO chat(message,from) VALUES('".$message."','".$from."')";
$result['send_status']=$conn->query($sql);

}
//print massages
$start =isset($_GET['start']) ? intval($_GET['start']):0;
$items = $conn->query("SELECT * FROM chat WHERE id > ".$start);
while ($row=$items->fetch_assoc()) {
$result["items"][]=$row;
}

$conn->close();

header('Access-Control-Allow-Origin: * ');
header('Control-Type: application/json');

echo json_encode($result);
? >

And below is the code in my index page:

<!DOCTYPE html>

<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>CHAT</title>
<script src="jquery.min.js"></script>
<script>
    var from = null, start = 0, url = "http://localhost/chat.php";
    $(document).ready(function () {
        from = prompt("enter your name");
        load();

        $('form').submit(function (e) {
            $.post(url, {
                message: $('#message').val(),
                from: from
            });
            $('#message').val('');
            return false;
        })
    });

    function load() {
        $.get(url + '?start=' + start, function(result) {
            if (result.items) {
                result.items.forEach(item => {
                    start = item.id;
                    $('#messages').append(renderMessage(item));
                    console.log(item.status);
                })
            };
            load();
        });
    }

    function renderMessage(item) {
        console.log(item);
    }


</script>

body { margin: 0; overflow: hidden; background: silver; } #messages { height: 83vh; overflow: hidden; padding: 10px; } form { display: flex; } input { font-size: 1.2rem; padding: 10px; margin: 10px 5px; appearance: none; -webkit-appearance: none; } #message { flex: 2; }
GET JSON

<div id="messages"></div>
<form>
    <input type="text" id="message" autocomplete="off" autofocus placeholder="Type Message...">
    <input type="submit" value="Send">
</form>

Thanks in advance.

How can i integrate a bitcoin payment method on my php website

Elijah Emmanuel — Sun, 23 May 2021 10:50:16 +0000

Please, how can i integrate a bitcoin payment method on my php website just like PayPal payment.

Am currently working on a payment system using php and sql and really need to know about how to integrate this bitcoin payment method.

How can i create a CRON operation to add numbers based on timed events in my database.

Elijah Emmanuel — Sat, 27 Mar 2021 15:28:50 +0000

please, how can i create a cron operation that will add numbers to the existing numbers based on my present database value when the next event is to be executed?

here is the code below:

<?php
$sql="CREATE EVENT test_event_05
ON SCHEDULE EVERY 1 MINUTE
STARTS CURRENT_TIMESTAMP
ENDS CURRENT_TIMESTAMP + INTERVAL 1 HOUR
DO
   INSERT INTO messages(email,income,created_at)
#i would like to add 20 at the next execution so that the income which is 30 would change to 60;

   VALUES('elijahemmanuel05',30,NOW());";

  if($conn->query($sql) == "true"){
    echo 'created';
  }else {
    die("not created".$conn->error);
  }
?>

please help me guys, its urgent

the reg

Elijah Emmanuel — Fri, 19 Mar 2021 18:31:46 +0000

FORM

<?php
include_once('header.php');
include('../validate/register.php');
?>




<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="./styles/nubastyle.css">
    <link rel="stylesheet" href="../styles/flick/flickity.css">
    <script src="../styles/flick/flickity.pkgd.min.js"></script>
    <script src="../styles/jquery/jquery.min.js"></script>
    <link rel="stylesheet" href="../public/styles/style.css">
    <title>LIBRARY SIGNUP</title>
</head>
<style>

</style>

<body>

    <br>
    <div class="container ml-lg-5 mr-lg-5">


        <div class="row  ml-lg-5 mr-lg-5 p-lg-5">
            <div class="col  ml-lg-5 mr-lg-5 p-lg-5 shadow">
                <form action="" method="POST">

                    <label for="username"><i class="fa fa-user"></i>User Name</label>
                    <input type="text" name="username" class="form-control">
                    <div class="text-danger"><?php echo $username_err?></div><br>


                    <label for="regno">Reg No</label>
                    <input type="text" name="regno" class="form-control">
                    <div class="text-danger"><?php echo $regno_err?></div><br>

                    <label for="email"><i class="fas fa-envelope"></i>Email </label>
                    <input type="email" name="email" class="form-control" required>

                    <label for="department"> <i class="fa fa-house-user"></i> Department</label>
                    <input type="text" name="department" class="form-control">

                    <label for="password"><i class="fa fa-key"></i> Password</label>
                    <input type="password" name="password" class="form-control" required>

                    <input type="submit" value="SUBMIT" class="btn btn-outline-primary">
                </form>
            </div>
        </div>
    </div>


    <?php include_once('../public/bottom.php')?>

</body>


</html>

PHP CODE

<?php 
$regno_err=$username_err="";
if($_SERVER["REQUEST_METHOD"] == "POST"){
if (preg_match('/^[a-zA-Z0-9]+$/', $_POST['username']) == 0) {
    $username_err='Username is not valid!';
}
    if(empty(trim($_POST['regno']))){
        $regno_err="please fill in this field";
    }elseif($stmt = $conn->prepare('SELECT id, username FROM user WHERE regno = ?')) {
        // Bind parameters (s = string, i = int, b = blob, etc), hash the password using the PHP password_hash function.
        $stmt->bind_param('s', $_POST['regno']);
        $stmt->execute();
        $stmt->store_result();
        // Store the result so we can check if the account exists in the database.
        if ($stmt->num_rows > 0) {
            // Username already exists
            $regno_err= 'regno exists, please choose another!';



        } else {
            $sql="INSERT INTO user(username,regno,email,password,department) VALUES(?,?,?,?,?)";
            if($stmt=$conn->prepare($sql)){
                $password=password_hash($password,PASSWORD_DEFAULT);
                $username=mysqli_real_escape_string($conn,$_POST['username']);
                $regno=mysqli_real_escape_string($conn,$_POST['regno']);
                $email=mysqli_real_escape_string($conn,$_POST['email']);
                $department=mysqli_real_escape_string($conn,$_POST['department']);

                $stmt->bind_param('sssss',$username,$regno,$email,$password,$department);
                if($stmt->execute()){
                    ECHO '<script>alert("SUCCESSFULLY REGISTERED")</script>';
                }
            }else{
                echo "something went wrong";
            }
        }

    } else {
        // Something is wrong with the sql statement, check to make sure accounts table exists with all 3 fields.
        echo 'Could not prepare statement!';
    }
}$conn->close();
?>

How Can i create a Secure SignIn Portal In PHP after Using Password Hash on SignUp Page.

Elijah Emmanuel — Fri, 19 Mar 2021 17:46:42 +0000

Please fellow Devs, i just created a Signup(Registration) Portal in PHP using password Hash to store my password in the Database, but i cannot Login to the welcome page because the password passed from the login page is not the same as the Hashed password in the database.
Here is the code below:
someone should please tell me whats wrong, thanks.

FORM

<?php
include_once('../public/header.php');
include('../validate/login.php');
?>

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="../public/styles/style.css">
    <title>student login</title>
</head>


<body>

    <div class="container ml-lg-5 mr-lg-5">
        <div class="row ml-lg-5 mr-lg-5 p-lg-5">
            <div class="col ml-lg-5 mr-lg-5 p-lg-5 shadow">
                <form action="" method="POST">
                    <div class="text-danger"><?php echo $err_msg ?></div>
                    <label for="regno">Reg No</label>
                    <input type="text" name="regno" class="form-control">
                    <div class="text-danger"><?php echo $regno_err ?></div>

                    <label for="password">Password</label>
                    <input type="password" name="password" class="form-control">
                    <div class="text-danger"><?php echo $password_err ?></div>

                    <input type="submit" value="LOGIN" class="btn btn-outline-primary">
                </form>
            </div>
        </div>
    </div>


</body>

</html>

FORM VALIDATION CODE

<?php
$err_msg = $regno_err= $password_err= "";
if($_SERVER["REQUEST_METHOD"] == "POST"){

    if ( !isset($_POST['regno'], $_POST['password']) ) {
        // Could not get the data that should have been sent.
        $err_msg='Please fill both the username and password fields!';
    };

    if(empty(trim($_POST['regno']))){
    $regno_err="please fill in regno";
    }elseif ($stmt = $conn->prepare('SELECT * FROM user WHERE regno = ?')) {
        // Bind parameters (s = string, i = int, b = blob, etc), in our case the username is a string so we use "s"
        $stmt->bind_param('s', $_POST['regno']);
        $stmt->execute();
        // Store the result so we can check if the account exists in the database.
        $stmt->store_result();

        if($stmt->num_rows == "false"){
            $regno_err= "user does not exist";
        }else{
            $regno=$_POST['regno'];

            $sql = "SELECT * From user WHERE regno = '{$regno}' ";
            $query = mysqli_query($conn, $sql);

            if(!$query){
                die('unable to query'.$conn->error);
            }


             while($row = mysqli_fetch_array($query)) {
                    $id            = $row['id'];
                    $username     = $row['username'];
                    $regno_in      =$row['regno'];
                    $email         = $row['email'];
                    $department   = $row['department'];
                    $pass_word     = $row['password'];
                }



            $password=password_verify($pass_word,$_POST['password']);
            if($regno_in ==$regno && $pass_word == $password){
                echo "you are welcome";
                $_SESSION['password'] = $pass_word;

                echo "your email is:".$_SESSION['password'];
            }else{
                echo "password does not match db";
            }

            }

        $stmt->close(); 
        }
    }$conn->close();
?>

How can i deliver the best in PHP to my clients without having full php skills

Elijah Emmanuel — Wed, 17 Mar 2021 10:37:33 +0000

Please fellow developers, How can i deliver the best website in PHP to my clients without having full php skills?
And is it alright to build up the website, launching it online and understanding how to works before going back to learn the code fully just to save time and deliver my work?
Will that also make me a lazy developer?
Please, help me, I need ur advice, please.

How to integrage bitcoin payment method in React

Elijah Emmanuel — Wed, 27 Jan 2021 03:55:06 +0000

Please, how can i integrate a bitcoin payment method on react js web app, just like a PayPal payment.

Am currently working on a web app with react js and really need to know about how to integrate this bitcoin payment method.

How to integrage bitcoin payment method in React. Js

Elijah Emmanuel — Tue, 26 Jan 2021 20:24:46 +0000

Please, how can i integrate a bitcoin payment method on react js web app, just like a PayPal payment.

Am currently working on a web app with react js and really need to know about how to integrate this bitcoin payment method.