Posting list of items from HTML form to PHP

Question

What I am trying to achieve is to have an undefined number of input fields (users are able to add additional input fields with a plus-button on the site). Each input field will have their id/name appended with an increasing number. This is already working fine.

Example:

<input type="text" name="field1" id="field1">
<input type="text" name="field2" id="field2">
<input type="text" name="field3" id="field3">
<button id="addanotherinputfield">+ Add new</button>

So in theory, there could be well more than 200 input fields, the last one then being:

<input type="text" name="field200" id="field200">

I currently push this as $_POST (code simplified):

<?php
    $db = new PDO("mysql:host=localhost;dbname=$dbname", $dbtable, $dbpass);
    $sdh = $db->prepare('INSERT INTO yeehaw (name,value) VALUES (:name,:value)');
    if($_POST['field1'] !='') {
        $name = 'field1';
        $value = $_POST['field1'];
        $sdh->bindParam(':name', $name);
        $sdh->bindParam(':value', $value);
        $sdh->execute();
    }
    if($_POST['field2'] !='') {
        $name = 'field2';
        $value = $_POST['field2'];
        $sdh->bindParam(':name', $name);
        $sdh->bindParam(':value', $value);
        $sdh->execute();
    }
    if($_POST['field3'] !='') {
        $name = 'field3';
        $value = $_POST['field3'];
        $sdh->bindParam(':name', $name);
        $sdh->bindParam(':value', $value);
        $sdh->execute();
    }
    $db = null;
?>

Currently this is working as well.

But for obvious reasons this is not a good way to do it, since it's not scalable (I have to add each case to the code and I like to clean out unnecessary code). I have googled for quit a bit now and can't seem to find the answers to two basic questions (maybe I am looking for the wrong terms/terminology?):

1. How can I make my PHP scale? So it doesn't matter if there is 1 or 1.000.000 input fields without having to list each case in the code (like a loop/foreach)?
2. Would it be better to open and close a DB connection for every case or do it like my example above? Isn't there a way to open one connection and push all added information at once? How would I go about this?

Any pointers/helpers much appreciated.

Answer 1

HTML

Set the name attribute of your HTML input to be an array to PHP:

<input type="text" name="field[]" />

this way the fields will post as an array an you can easily loop over every field in PHP.

PHP

foreach($_POST['field'] as field){
    // handle input
}

Answer 2

To make your code much more scalable and less redundant or repeatable i would suggest using a PDO dynamic and automated data binding such as the one listed on Github, its helpful when binding multiple data I have used it a couple of times. It does all the binding for you, here is a link to it on GitHub https://github.com/JstMagic/dynamicPDO Use it in conjunction to Tiles Answer

<input type="text" name="field[]" />

  foreach($_POST['field'] as field){ // handle input }