dropdown box value's default value shows what is saved in database. - php

Question

I have a dropdown box, and this is the format for the create.blade.php
<div class="col-sm-6">
<label for="order_mode">Order Mode</label>
<select class="form-control" id="order_mode" name="order_mode">
<option value="fcfs">First Come, First Serve</option>
<option value="pre-selling">Pre-Selling</option>
<option value="purchase-order">Purchase Order</option>
</select>
</div>
I want to use the same format for the edit.blade.php but I want to show what the selected value is as the default, and when I change it and hit update, then the changes will be saved.
the value for the order_mode is denoted by value="{{ $product->order_mode }}"

Answer 1

You can use AJAX to POST your variable to your edit.blade.php file. Personally, I use jQuery AJAX, simply because it's easy to read and understand. I also encapsulated the AJAX function into another function that you can call in your update button via onclick. However, you could also add this functionality directly to the AJAX function via an onclick event, however, note that in that case, you will need to put that into a document.ready function, so I figured encapsulating the function would make for easier understanding.
Note that you will need to include a jQuery library for this example to work. However, it's no different from including any other JS file or similar.
Example:
<script src="/js/jquery.min.js" type="text/javascript"></script>
/js/ being your JavaScript folder in your directory.
function updateSelection()
{
$.ajax({
type : "POST",
url : "/edit.blade.php",
data : {
selection: $("#order_mode")val()
},
success: function (html) {
/* here you can do something on success if you want.
I.e. redirect to another page etc. */
}
})
}
As for updating the value, I assume that you are storing the data into a database? If not, then you have to, or else there is no way of knowing what was selected in the future. So, going by that you are in fact storing the selected data into a database, your edit.blade.php file will need to fetch the parsed value (I named it selection in this case), and store it in the database.
<?php
/* Note that we used a "POST" method, so in order to
retrieve our parsed variable, we'll have to use $_POST. */
$selected=$_POST['selection'];
/* We then need to store it into the database.
Note that I don't know what mysql extension you use (mysql_*, mysqli_* or PDO).
I will use mysqli_* in my example, and $conn is your
database connection variable. */
/* Note that you will also need the user ID in order to know which user
updated their selected value. You will also need to check if the selection
already exists or not, because if it doesn't, you will have to perform an insert,
and if it does, you will have to perform an update in your query statement. */
//check if user selection already exists, or whether it's the users first selection.
$sql = "SELECT COUNT(column_name_for_user_id) FROM your_table_name
WHERE user_id_column='$your_user_id_variable'";
$result_set = mysqli_query($conn, $sql);
$check = mysqli_fetch_array($conn, $result_set )[0];
if($check > 0)
{
$sql = "UPDATE your_table_name SET column_name_for_selection='$selected'
WHERE column_name_for_user_id='$your_user_id_variable'";
}
else
{
$sql = "INSERT INTO your_table_name SET column_name_for_selection='$selected'
AND column_name_for_user_id='$your_user_id_variable'";
}
mysqli_query($conn, $sql);
/* I would recommend that you look into
prepared statements and/or sanitizing inputs */
?>
Important: In terms of the user ID, I do NOT recommend parsing it through AJAX, as it is something that is handled client side, meaning that it is fully editable by the client through the browser's dev tools. Instead, use a session.
Example of session variable:
<?php
session_start(); //starts the session on the page.
$your_user_id_session_variable = $_SESSION['$your_logged_in_users_user_id'];
?>
You will need to set this session upon user login, where you fetch the users data upon login success, and set the session variable.
Now back to your <select>. We will have to check for what is selected. You will have to retrieve the selected value from the database, using your user's user ID to fetch it.
Remember what I mentioned about sessions.
Example:
<?php
//$conn is your connection variable
$sql = "SELECT column_name_for_selection FROM your_table_name
WHERE user_id_column='$your_user_id_sessin_variable'";
$result_set = mysqli_query($conn, $sql);
$selected = mysqli_fetch_array($conn, $result_set )[0];
?>
You can now use your $selected variable to check for what was selected by the user, and it will always have that as its default selection.
<select class="form-control" id="order_mode" name="order_mode">
<option value="fcfs" <?php if($selected == "fcfs"){ echo 'selected="selected"'; } ?> >First Come, First Serve</option>
<option value="pre-selling" <?php if($selected == "pre-selling"){ echo 'selected="selected"'; } ?> >Pre-Selling</option>
<option value="purchase-order" <?php if($selected == "purchase-order"){ echo 'selected="selected"'; } ?> >Purchase Order</option>
</select>
Please note, that you will need to declare:
<?php
session_start();
?>
at the beginning of every file where you wish to use the session(s).
And now for the last bit, your update button.
<button id="updateButton" name="updateButton" onclick="updateSelection();">Update</button>
Long post... but I hope it helped, or at least gave some insight to how it could be done.