HELP HELP HELP - passing a variable

[webAmeteur]

Ok here is my situation, I have a project due in 2 days in which I have come to a huge mountain and havent been able to get any further with in about 2 weeks.

I have a query from my database selecting 2 values:
seat_number (which has values 1 to 100)
seat_status (either EMPTY or BOOKED)

Here is my code:
<?php

$result = mysql_query($query_rstAvailSeats);
$x = 1;

echo '<table align="center"><tr>';

while($disp = mysql_fetch_array($result)){

if ($disp['seat_status'] == 'EMPTY')
{

	echo '<td><img src="../Images/chair.jpg"  onClick=addSeat()>';
	echo $disp['seat_number'];
}
else
{
	echo '<td><img src="../Images/chairBooked.jpg" onClick=alert("Booked")>';
	echo $disp['seat_number'];
}
if($x%5==0){ 
    echo '</tr>'."\n". 
          '<tr>'."\n"; 
} 
if($x%25==0){
	echo '</tr>'."\n". 
         '<tr></tr>'."\n". 

		  '<tr>'."\n"; 
} 
$x = $x+1; 

}
echo '</tr>'."\n".
'</table>';
?>

This displays a 5x20 table, each cell having a picture of an empty chair is seat_status is EMPTY or a chair with a cross if seat_status is BOOKED.

I need it, so when a user clicks on a chair, lets say chair 25, the value is passed SOMEWHERE (i'm not sure where, i was thinking a javascript array) so when the user clicks on a submit button, the chair values he has selected can be passed back to the database, and their seat_status changed from EMPTY to BOOKED.

I would also like the picture to change from an empty chair to a booked one.

I know this may seem alot but I am in real trouble if I dont get this done, and I have been trying for weeks now. Ive been to every possible internet site on the net I should think.

Many Many thanks

[devinemke]

i suggest you make the entire matrix into a form with a checkbox next to each seat to indicate the seat_status. here is a very simplified example:

<?php
if (!isset($_POST['submit']))
{
	echo '
	<form action="" method="POST">
	<input type="checkbox" name="seats[]" value="1">seat 1<br>
	<input type="checkbox" name="seats[]" value="2">seat 2<br>
	<input type="checkbox" name="seats[]" value="3">seat 3<br>
	<input type="checkbox" name="seats[]" value="4">seat 4<br>
	<input type="checkbox" name="seats[]" value="5">seat 5<br>
	<input type="submit" name="submit" value="submit">
	</form>
	';
}
else
{
	// just echoing the query for testing
	$sql = "UPDATE table SET seat_status = 'booked' WHERE seat_number IN(" . implode(',', $_POST['seats']) . ")";
	echo $sql;
}
?>

[webAmeteur]

I have used checkboxes, but the project spec says I am not allowed to use them. The spec says "A visual display i.e pictures that the user can click on to book seats",

After I posted the first message, I managed to pass the seat_number to a javascript array I think using:

<SCRIPT language="Javascript">
function addSeat(value){
var i = 0
i = value
var seatArray = new Array(100)
seatArray[value] = value;

}

<?php
.
.
.
echo '<td><img src="../Images/chair.jpg" onClick=addSeat(' . $disp['seat_number'] . ')>';
.
.
.
?>

From this I believe the seats the user clicks on are in an array, but how do I use these values to return back to PHP so I can update the database???

Kind Regards

[Kudose]

Why not give each seat a PHP_SELF form, with the images as image submit buttons with name values. When clicked, store them into a session array. Then when your "master" submit button is clicked, just pass the session array.

Does that make any sense? I am kinda...out of it.

[webAmeteur]

I sort of see where you are going with this. So would each table data be an <A HREF ... instead og <IMG SRC ...

If this is the case, then what code do I need so when the user clicks on the image to pass the seat_number to a session array.

I have never used session arrays before

Kind Regards

[Roger_Ramjet]

Hi webAmatuer, still working on this one eh. No it would be an <input type="image" . See this for full details on input elements. Remember to use the 'disabled' keyword for the booked seats, don't want the form submitting a booked seat. And the syntax is

<input type="image" name="seat1" align="texttop" value="1" alt="click to book this seat" src="../Images/chair.jpg" >

or

<input type="image" name="seat1" align="texttop" value="1" alt="this seat is already booked" src="../Images/chairBooked.jpg" disabled >

[devinemke]

Kudose solution who require the page be reloaded for each seat clicked which seems a bit unecessary. how bout having each click simply add a seat number to a comma separated text form field. here again is a very simple example:

<html>
<head>
<title>test</title>
<script language="javascript">

function addSeat(value)
{ 
	var list = document.forms[0].list.value;
	if (list) {value = "," + value;}
	document.forms[0].list.value = list + value; 
}

</script>
</head>
<body bgcolor="white">

<?php
if (!isset($_POST['submit']))
{
	echo '
	<a href="#" onclick="addSeat(1)">seat 1</a><br>
	<a href="#" onclick="addSeat(2)">seat 2</a><br>
	<a href="#" onclick="addSeat(3)">seat 3</a><br>
	<a href="#" onclick="addSeat(4)">seat 4</a><br>
	<a href="#" onclick="addSeat(5)">seat 5</a><br>

<form action="" method="POST">
<input type="text" name="list"><br>
<input type="reset" name="reset" value="reset"> <input type="submit" name="submit" value="submit">
</form>
';
}
else
{
	// just echoing query for testing
	$sql = "UPDATE table SET seat_status = 'booked' WHERE seat_number IN(" . $_POST['list'] . ")";
	echo $sql;
}
?> 

</body>
</html>

be advised: this simple example does not include any form validation.

[Roger_Ramjet]

Good suggestion devinmke.

Everyone of us seems to have overlooked the usual problem with this kind of thing, concurrent users trying to book the same seat.

Is this a real app or are you doing a student project? Either way it has to be catered for.

When booking are submitted you will first have to check if the seats are still available before you book them. This will need to lock tables so that the do not get booked between your check and your update.

If they, or some, have been booked then you can use the number and location to search for the nearest alternatives to present to the users when you tell them sorry, too late.

[Roger_Ramjet]

Just one additional point, I'd tend to use a hidden field rather than text to store the list. If the user can see it and edit it then someone will, and they'll add a seat that is already booked, just because that is what users do.

[webAmeteur]

Thanks very very much Devine and Roger. This is a student app, the point about someone booking a seat that is already booked, I hope is sorted in the fact that that it is disabled anyway if someone goes to book it.

I have tried both methods,
1) using the javascript function to add the seat number selected to a text box and
2) using the <image type ... way

Which way would you suggest that will be easier for me to take these values, and then to use them in updating the database.

Sorry if these are dumb questions. If they are its prob cos im dumb...

Kind Regards

[devinemke]

as i pointed out before, using client-side code to collect all of the seats first is preferable to submitting the form for each seat. be sure to properly validate the incoming data.

[webAmeteur]

Ok, at the moment I ma putting the values in 1 textbox seperated by commas e.g. 1, 3, 4, 77, 89

Will 1 textbox be ok when i need to take these values and submit them to the database, or should i put them in seperate textboxes having 1 value per box???

Regards

[Roger_Ramjet]

You missread me webby.

I am saying that in a multi-user environment, I get the page with available seats and then devine mike gets the same page with the same list of available seats.
I click to book seats 20, 21, 22 and submit them and they are booked.
Mike meanwhile is still seeing them as unbooked, so he selects then because they are good seats.

When he comes to submit his selection it is too late, I've booked them. If you don't check this first then he will get a booking for seats that are already booked.

Now, you may not have time to implement this. But you must work out how it would be done and include that as a text with pseudo code so that your teachers can see what you would do given more time. It is the sort of thing that will turn a good mark into a distinction. If they have not included it in the project spec then use my notes to point out why it is neccessary and why you have added it to your design.

[devinemke]

why does everyone on the board call me mike?

[webAmeteur]

Ok I see Roger, i think that will be good to boost the mark a bit.

Went to see my lecturer today, he told me very bluntly under no circumstance would I get any help. Only 1 word for him, prob not suitable for this forum though.

It is the invisible 'I' in devinemke name. Can you not see it???

Anyway back to this coding, when writing the UPDATE for the database, using the seat_number, say if the user selects 4 seats, will I have to create 4 updates, or is there a way to do it in 1???

Also how do I get the values out of the texbox that addSeats put them in, into the PHP update code??

Thanks

[Roger_Ramjet]

Originally posted by devinemke
why does everyone on the board call me mike?

Why does everyone on the board call me Roger? My name is David. 😕

[devinemke]

Originally posted by Roger Ramjet
Why does everyone on the board call me Roger? My name is David.

well dave, considering what my board handle is and what your's is, i think that calling you Roger is a pretty honest mistake. calling me Mike is less so.

[Kudose]

why does everyone on the board call me mike?

For a while there, I always just glanced at your handle and saw devinemike instead of devinemke, so...looks like I am not the only one...

But I have known better for a few months now.

[devinemke]

perhaps my custom title will now make this more clear

[Roger_Ramjet]

Nope. Your flashing eyes are all I see.