Calculating Value After Form Submission

goclimb

Hi,

I have a simple form that the user will input two datapoints into : the current date and their weight. That information will be put into a database. Along with that, I would like to calculate their BMI (Body Mass Index) based on their weight, and insert that info to the database as well. Then want to present a page with a chart containing all their datapoints to date. The flow would be like this:

Input Date
Input Weight
Hit Submit
Calculate BMI
Insert Date, Weight, BMI values into database
Present page with all Date/Weight/BMI values to date

How's the best way to do this? Here's the current code I have:

<?php
$db = mysql_connect("localhost", "xxxxx", "xxxxx");
mysql_select_db("fitness",$db);
if ($submit) {
$sql = "INSERT INTO mark (date,weight) VALUES ('$date','$weight')";
$result = mysql_query($sql);
header ("Location: http://www.somewhere.com/status.php");
} else {
?>
<html>
<head>
<title>Weight Input</title>
</head>
<body marginwidth="0" marginheight="0" leftmargin="0" topmargin="0" bgcolor="#FFFFFF">

<TABLE BORDER=0 CELLSPACING=2 CELLPADDING=2>
<FORM METHOD="post" ACTION="<?php echo $PHP_SELF?>">
<TR>
<TD ColSpan=1 RowSpan=1 Align=Left>
Date:
</TD>
<TD ColSpan=1 RowSpan=1 Align=Left>
<INPUT TYPE="text" NAME="date" SIZE=10>
</TD>
</TR>
<TR>
<TD ColSpan=1 RowSpan=1 Align=Left>
Weight:
</TD>
<TD ColSpan=1 RowSpan=1 Align=Left>
<INPUT TYPE="text" NAME="weight" SIZE=10>
</TD>
</TR>
<TR>
<TD ColSpan=2 RowSpan=1 Align=Center>
<INPUT TYPE="submit" NAME="submit" VALUE="Submit"> <INPUT TYPE="reset" VALUE="Reset">
</TD>
</TR>
</FORM>
</TABLE>
<?php
} // end if
?>
</body>
</html>

Any help would be greatly appreciated!

Thanks,

Mark

thorpe

i have no idea how to calculate someones BMI, but im sure its simple maths.

arithmetic operators

goclimb

I understand how to calculate the BMI. What I'm not understanding is how, after the user inputs his weight, can I calculate the BMI and have the data put into the database before presenting the summary to the user. Can I do it before he hits the submit button? Or after the button is hit, but before the values are put into the database? That's where my confusion lies.

Thanks!

thorpe

sorry. put it just before your INSERT. so;

if ($submit) {
// do calculations
$BMI = $a + $b;
// do insert using $BMI

ps; you might want to move these lines inside the 'if' statement aswell;

$db = mysql_connect("localhost", "xxxxx", "xxxxx");
mysql_select_db("fitness",$db);

no point in opening the db untill you need it.

goclimb

Wow...that was much easier than I thought it would be. It works...thanks for the info!

Mark