PHP foreach Construct Confusion - php

Question

I am having a hard time wrapping my head around the foreach construct. I have found numerous examples of course, but I never seem to be able to adapt them to my needs.
Please consider this working example I have:
I am collecting two dates in an HTML form:
<form method="post">
<legend>Minutes and Records</legend>
<label for="FirstAGMDate">First AGM Date (only if known)</label>
<input type="text" name="FirstAGMDate" value="2014-01-01" />
<label for="MinutesInspectedFromDate">Minutes Inspected From Date</label>
<input type="text" name="MinutesInspectedFromDate" value="2014-01-02" />
<input type="submit" name="submit" />
</form>
On submit the values are being pushed to the mysql database with a PDO prepared statement:
if (isset($_POST['submit'])) {
$sql = "UPDATE jobsinglevalues SET Date = :FirstAGMDate WHERE FormId = 0;
UPDATE jobsinglevalues SET Date = :MinutesInspectedFromDate WHERE FormId = 1;";
$sth = $db->prepare($sql);
$sth->execute(array(':FirstAGMDate'=>($_POST['FirstAGMDate']), ':MinutesInspectedFromDate'=>($_POST['MinutesInspectedFromDate'])));
}
This works no problem, but it's not very clever when I need to repeat this for a dozen inputs. What I want to do is achieve this with only one line of sql; looping for each <input type="text" name="Value" />.
How can I place this into a foreach loop?
In my head it works like this:
On submit each input updates the value in the database based on FormId, which increments by 1 each loop starting at 0. FormId is not a primary key, it simply mirrors the order in which the form elements are displayed.
Update - working example
if (isset($_POST['submit'])) {
$FormId = 0;
foreach($_POST['Value'] as $avalue){
$sql = "UPDATE jobsinglevalues SET Date = :Value WHERE FormId = :FormId";
$sth = $db->prepare($sql);
$sth->execute(array(':Value'=>($avalue), ':FormId'=>($FormId)));
++$FormId;
}
}
This seems to logically work to me! Is the correct solution similar? Please let me know if I need to clarify anything.
Thankyou,
Sam

Answer 1

Let's start by making sure all our values are in an array after posted; if you don't care about the keys you can just use name="Values[]", but I'll use name="Value[FirstAGMDate]" etc so we know what key a value belongs to.
<form method="post">
<legend>Minutes and Records</legend>
<label for="FirstAGMDate">First AGM Date (only if known)</label>
<input type="text" id="FirstAGMDate" name="Value[FirstAGMDate]" value="2014-01-01" />
<label for="MinutesInspectedFromDate">Minutes Inspected From Date</label>
<input type="text" id="MinutesInspectedFromDate" name="Value[MinutesInspectedFromDate]" value="2014-01-02" />
<input type="submit" name="submit" />
</form>
Now we can process the posted array of values. If we want to do something with the key, we can use foreach($_POST['Value'] as $akey => $avalue), if we are only interested in the values then foreach($_POST['Value'] as $avalue) suffices.
$sql = "UPDATE jobsinglevalues SET Date = :Value WHERE FormId = :FormId;";
$sth = $db->prepare($sql);
foreach($_POST['Value'] as $akey => $avalue) {
$sth->execute(array(':Value' => $avalue, ':FormId'=> $FormId ));
++$FormId;
}
[edit] As per edit-suggestion by #AravindKishore, creating the prepared statement is better done before the loop. Prepare once, enjoy forever.