Gain insights into building a modern, production-ready PHP app. Delve into CRUD operations, I/O security, routing, and more. Discover how to effectively use PHP and MySQL for database applications.

Build a CRUD Database App with PHP & MySQL-01.png

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Learning a programming language is one thing and using it to build something great is another. I've been teaching code newbies and aspiring developers for a long time and I see many of them struggling to put into practice their newly acquired skills. I've also noticed that many resources on the Internet are out-of-date, misleading, or don't provide real hands-on practice.

I've built this course to fix the issues above. You'll learn a better way to build a modern and production-ready PHP app connected to a database like a pro. The app, a CRUD one, will also have some more advanced features like I/O security, router, and more. 

At the end of this course, you'll be well equipped to build database apps with PHP.

Hands-on PHP & MySQL: Build a CRUD Application

As in the previous lesson, we’ll learn how to remove a record from the database. At the end of the lesson, our assignment will be to write code to delete a project. 

The main keyword for this lesson is `DELETE`.

# Getting started
Below is the user story for this feature:
> Title: Deleting a task
>
> **Story**<br>
> As a user, we’d want to see a “Delete” button next to the task list, so that we could delete a task from the database.
>
> **Acceptance Criteria**<br>
> Scenario: The task that is selected for deletion should be removed from the database. Given that a user previously selected a task for deletion and we have four tasks in the list, we should have three tasks in the database. 

From the user story written above, we can understand that the implementation of this feature can be divided into two tasks, the delete button, and its handler.

# The *delete button*

**The view**

Let’s create our “Delete” button into a form so that we can easily handle it.

Going to `views/task_list.php`, we’ll edit the code that displays the list of tasks like this:

```
<li>
            <?php echo escape($task["title"]) ?>
            <form method="post">
                <input type="hidden" value="<?php echo $task["id"]; ?>" name="delete">
                <input type="submit" value="Delete">
            </form>
</li>
```
Nothing tricky here. We created a hidden input that will help us get the `id` of the task.

Now, let's handle the form.

# The handler
 
In the controller, `controllers/task_list.php`, we’ll check if the user has submitted the form. Then we’ll call the `delete` function:

```
if (isset($_POST['delete'])) {
    if (delete_task($_POST['delete'])) {
        header('location: task_list.php?msg=Task+deleted');
        exit;
    } else {
        header('location: task_list.php?msg=Couldn\'t+delete+the+task');
        exit;
    }
}

if (isset($_GET['msg'])) {
    $error_message = $_GET['msg'];
}
```
We need to create the `delete_task()` in the model:

```
function delete_task($id)
{
    try {
        global $connection;

        $sql =  'DELETE FROM tasks WHERE id = ?';
        $task = $connection->prepare($sql);
        $task->bindValue(1, $id, PDO::PARAM_INT);
        $task->execute();

        return true;
    } catch (PDOException $exception) {
        echo $sql . "<br>" . $exception->getMessage();
        exit;
    }
}
```

Let’s put it all together and run the code to see how it works.

Sometimes updating records is not enough and we may need to delete the record.

Introduction

App Initialization

Create and Read Records

Refactor the Application

PHP Data Validation

Generate Reports

Update and Delete Records

PHP Router

Conclusion

Appendix

Remove Records