php – Updating data in database base on id?

December 21, 2021

I am working on a project that takes students attendance in class and I want to update the database data through PHP whilst running a SQL function of UPDATE, but I want to be able to update it base on the id of the data.

This is the code that I am working with at the moment.

<?php

require_once './dba.php';

$status = "";

if(isset($_POST['time_in'])) {

    $query = "INSERT INTO nameOfTable (datetime) VALUES (NOW())";

    $d = $conn->prepare($query);

    $d->execute();     

} elseif(isset($_POST['time_out'])) {
    $query = "UPDATE nameOfTable SET datetime = NOW() WHERE id = ? ";

    $d = $conn->prepare($query);

    $d->execute();     
} else {
    $status = "Can't time in!";
}

>Solution :

Use $conn->lastInsertId() to get the ID that was assigned when they clocked in. Save that in a session variable and use it when they clock out.

<?php

require_once './dba.php';

$status = "";

if(isset($_POST['time_in'])) {
    $query = "INSERT INTO nameOfTable (datetime) VALUES (NOW())";
    $d = $conn->prepare($query);
    $d->execute();     
    $_SESSION['clock_id'] = $conn->lastInsertId();
} elseif(isset($_POST['time_out'])) {
    if (!isset($_SESSION['clock_id'])) {
      $status = "You need to clock in first!";
    } else {
      $query = "UPDATE nameOfTable SET datetime = NOW() WHERE id = :id ";
      $d = $conn->prepare($query);
      $d->execute(['id' => $_SESSION['clock_id']]);   
    }
} else {
    $status = "Can't time in!";
}