Script posts the first number in value - php

Question

I am trying to post data to my database. When I post the data I can see that the first number of the value is posted to the database:
Example:
I want to post the value 15. The script posts 1.
I want to post the value 550. The script posts 5.
I want to post the value 30. The script posts 3.
Does someone know the reason for that?
Here is my script:
<input type="text" id="quantity" name="quantity" value="15" />
<input type="text" id="name" name="name" value="550" />
<input type="text" id="price" name="price" value="30" />
<?php
for($count=0; $count<$_POST["total_item"]; $count++)
{
$db3 = new PDO('mysql:host=localhost;dbname=db', 'root', 'pass');
$query3= "INSERT INTO scu_test(id, quantity, name, price) VALUES (:id, :quantity, :name, :price)";
$stmt3 = $db3->prepare($query3);
$exec3 = $stmt3->execute(array(
':id' => $_SESSION['id'],
':quantity' => $_POST["quantity"][$count],
':name' => $_POST["name"][$count],
':price' => $_POST["price"][$count]
));
if($exec3)
{
header('Location: ../succ.php');
}
}
?>
Update 1:
With the answer of Justinas I build the following script:
Dynamic rows:
<input type="text" id="quantity1" name="quantity" value="15" />
<input type="text" id="name1" name="name" value="550" />
<input type="text" id="price1" name="price" value="30" />
<input type="text" id="quantity2" name="quantity" value="15" />
<input type="text" id="name2" name="name" value="550" />
<input type="text" id="price2" name="price" value="30" />
Post:
<?php
foreach($_POST as $i => $item)
{
$db3 = new PDO('mysql:host=localhost;dbname=db', 'root', 'pass');
$query3= "INSERT INTO scu_test(id, quantity, name, price) VALUES (:id, :quantity, :name, :price)";
$stmt3 = $db3->prepare($query3);
$exec3 = $stmt3->execute(array(
':id' => $_SESSION['id'] . '_' . $i,
':quantity' => $_POST["quantity"],
':name' => $_POST["name"],
':price' => $_POST["price"]
));
if($exec3)
{
header('Location: ../succ.php');
}
}
?>
When I post the data to the database I get 18 rows in the database. The data that is posted looks like random data with has no relation with the values in quantity, name or price.
Does someone know what is wrong with the script?

Answer 1

To answer your first issue, the reason that you were only getting the first character of each field value is because you were trying to access the values as if they were arrays, but they were strings -- when you ask for [0] from a string, you will receive the character at the first "offset" aka the first character.
Furthermore, because you had your header() line inside your foreach() loop, you were never going to process more than one set of data before the redirect was executed. The redirect must go outside the loop to prevent causing an early exit.
As for prepared statements, the beauty of prepared statements is that you write the query only once and merely update the bound variables for subsequent executions. In the same vein, you should only create one database connection and keep using it in your script.
Now, as a matter of personal preference, you can choose to write one INSERT query with the entire batch of data or you can conduct several single-row INSERT queries.
As for your question update, you have created unique id values, but duplicated name values for your <input> tags. This means that when the form is submitted, you will not have all of the values in your $_POST array, you will have the "last iterated" set of data. The POST superglobal array is generated using the name values as keys and duplicates keys are not permitted on the same level of an array. So you will have something like this:
$_POST = ["quantity" => "15", "name" => "550", "price" => "30"];
The best advice I can give is to fix your html form. If you don't care about the number associated with each set of fields, use this syntax:
<input type="text" name="quantity[]" value="15" />
<input type="text" name="name[]" value="550" />
<input type="text" name="price[]" value="30" />
With empty square brackets in the name value, php will apply indexed keys while generating a multi-dimensional POST array.
$_POST = [
0 => ["quantity" => "15", "name" => "550", "price" => "30"]
];
If you want to have complete control over the numeric key generated for POST, then write whatever number you wish into the square brackets.
<input type="text" name="quantity[1]" value="15" />
<input type="text" name="name[1]" value="550" />
<input type="text" name="price[1]" value="30" />
<input type="text" name="quantity[4]" value="6" />
<input type="text" name="name[4]" value="577" />
<input type="text" name="price[4]" value="39" />
This generates:
$_POST = [
1 => ["quantity" => "15", "name" => "550", "price" => "30"],
4 => ["quantity" => "6", "name" => "577", "price" => "39"]
];
As for the querying, here is a fully tested demo snippet:
session_start();
$_SESSION['id'] = 44;
$_POST = [
1 => ['quantity' => '15', 'name' => '550', 'price' => '30'],
4 => ['quantity' => '16', 'name' => '551', 'price' => '30']
];
try {
$db = new PDO("mysql:host=localhost;dbname=db;charset=utf8", "root", "");
$stmt = $db->prepare("INSERT INTO scu_test (id, quantity, name, price) VALUES (:id, :quantity, :name, :price)");
foreach ($_POST as $key => $set) {
$exec = $stmt->execute([
':id' => "{$_SESSION['id']}_$key",
':quantity' => $set["quantity"],
':name' => $set["name"],
':price' => $set["price"]
]);
}
header('Location: ../succ.php'); // if error-free, then all successful; redirect
} catch(PDOException $e){
echo "Error message: " , $e->getMessage(); // do not show error messages to users when you go live
}
Inserted Data:
id | quantity | name | price
------|------------|--------|---------
44_1 | 15 | 550 | 30
44_4 | 16 | 551 | 30

Answer 2

It's because your posted data is not multi-dimensional array, but single array:
['quantity' => '', 'name' => '', 'price' => '']
How to fix it:
Add [#] to your HTML:
<div class="item">
<input type="text" class="quantity" name="[0]quantity" value="15" />
<input type="text" class="name" name="[0]name" value="550" />
<input type="text" class="price" name="[0]price" value="30" />
</div>
....
<div class="item">
<input type="text" class="quantity" name="[10]quantity" value="15" />
<input type="text" class="name" name="[10]name" value="550" />
<input type="text" class="price" name="[10]price" value="30" />
</div>
Then in PHP use foreach:
$db3 = new PDO('mysql:host=localhost;dbname=db', 'root', 'pass');
$query3 = "INSERT INTO scu_test(id, quantity, name, price) VALUES (:id, :quantity, :name, :price)";
foreach($items as $i => $item) {
$stmt3 = $db3->prepare($query3);
$result2 = mysqli_fetch_assoc($res2);
$exec3 = $stmt3->execute(array(
':id' => $_SESSION['id'] . '_' . $i, // Don't know why not using Auto-Increment field
':quantity' => $item["quantity"],
':name' => $item["name"],
':price' => $item["price"]
));
if(!$exec3) {
header('Location: ../error.php');
}
}
header('Location: ../succ.php');

Answer 3

Try this
<input type="text" id="quantity1" name="quantity[]" value="15" />
<input type="text" id="name1" name="name[]" value="550" />
<input type="text" id="price1" name="price[]" value="30" />
<input type="text" id="quantity2" name="quantity[]" value="15" />
<input type="text" id="name2" name="name[]" value="550" />
<input type="text" id="price2" name="price[]" value="30" />
your php:
foreach($_POST['quantity'] as $i => $item)
{
$db3 = new PDO('mysql:host=localhost;dbname=db', 'root', 'pass');
$query3= "INSERT INTO scu_test(id, quantity, name, price) VALUES (:id, :quantity, :name, :price)";
$stmt3 = $db3->prepare($query3);
$exec3 = $stmt3->execute(array(
':id' => $_SESSION['id'] . '_' . $i,
':quantity' => $_POST["quantity"][$i],
':name' => $_POST["name"][$i],
':price' => $_POST["price"][$i]
));
if($exec3)
{
header('Location: ../succ.php');
}
}

Answer 4

You should use array in name when using multiple possibilities
<input type="text" id="quantity1" name="quantity[]" value="15" />
<input type="text" id="name1" name="name[]" value="550" />
<input type="text" id="price1" name="price[]" value="30" />
<input type="text" id="quantity2" name="quantity[]" value="15" />
<input type="text" id="name2" name="name[]" value="550" />
<input type="text" id="price2" name="price[]" value="30" />
And in your php script you dont need to append $i in your $_SESSION['id'] just make it primary key and set auto increment in database and do not include it in query it will automatically incremented in each insertion:
<?php
foreach($_POST['quantity'] as $i => $item)
{
$db3 = new PDO('mysql:host=localhost;dbname=db', 'root', 'pass');
$query3= "INSERT INTO scu_test(quantity, name, price) VALUES (:quantity, :name, :price)";
$stmt3 = $db3->prepare($query3);
$exec3 = $stmt3->execute(array(
':quantity' => $_POST["quantity"][$i],
':name' => $_POST["name"][$i],
':price' => $_POST["price"][$i]
));
if($exec3)
{
header('Location: ../succ.php');
}
}
?>
This should insert values as they are if the problem still persists check the length in your database for column quantity, name and price. You need to set int(11) for column quantity, name and price if you want to store integer values and if you want to store alphanumeric values than it should be varchar(250)