no output at all -- can't see why in code (???)

ATS16805

hello. i just need a second (or 3rd, etc) pair of eyes to glance at this code to see if you can tell why i'm getting no screen output at all except for a notice about line 6 being an undefined variable.

this seems so simple, but i can't see anything wrong here! what am i missing?
😕

i have no idea if my script is goign to work cause i haven't been able to get past this silly thing! hmph!
:glare:

<?php
$conn = mysql_connect("localhost", "private", "private") or die(mysql_error());
mysql_select_db("cb_shows1", $conn) or die(mysql_error());
// MAKE DB CONNECTION

if ($_POST['op'] != "do_it") {
							  // BEGIN IF 'OP NOT EQUAL TO DO_IT' LOGIC

// QUERY FOR CONCTACT ID AND NAME
$contQuery = "select contact_id, contact_name from contact_info";
$contShow = mysql_query($contQuery) or die(mysql_error());

// BEGIN MAKING HTML BLOCK
	$html_variable = "<h1>Associate Contact with Artist info</h1>
					  <p>Use the pull-downs to match Contact person
					  to the appropriate Artist</p>
					  <form method=\"post\" action=\"$_SERVER[PHP_SELF]\">
					  <p><select name=\"contact_id\">
					  <option value=\"\">-- Contact Name --</option>";

	while ($contArray = mysql_fetch_array($contShow) or die(mysql_error()) ) {
																			  // START WHILE LOOP ONE
		$contId = $contArray['contact_id'];
		$contName = $contArray['contact_name'];		

$html_variable .= "<option value=\"$contId\">$contName</option>";

	}
	// END WHILE LOOP ONE

$html_variable .= "</select></p>";

// QUERY FOR ARTIST ID AND NAME
$artQuery = "select artist_id, artist_name from artist_info";
$artShow = mysql_query($artQuery) or die(mysql_error());

$html_variable .= "<p>Use this pull-down to match an Artist 
                   with the Contact selected above</p>
				   <p><select name=\"artist_id\">
				   <option value=\"\">-- Artist Name --</option>";

	while ($artArray = mysql_fetch_array($artShow) or die(mysql_error()) ) {
																		    // START WHILE LOOP TWO
		$artId = $artArray['artist_id'];
		$artName = $artArray['artist_name'];

	$html_variable .= "<option value=\"$artId\">$artName</option>";

	}
	// END WHILE LOOP TWO

	// MORE HTML VARIABLE CONCAT
	$html_variable .= "</select></p>";

	$html_variable .= "<p>When you are finished making your selections
					   simply hit the button below, and your selections will
					   be associated properly for future reference</p>
					   <p>
					   <input type=\"submit\" name=\"submit\" 
					   value\"Assciate Contact &amp; Artist Now\" /></p>
					   <input type=\"hidden\" name=\"op\" value=\"do_it\" />
					   </form>";

	}
	// IF LOGIC PART TWO SHOULD ACTIVATE UPDATE QUERY AND ASSOCIATE ARTIST AND CONTACT
	 else if ($_POST['op'] == "do_it") {

	// SQL -UPDATE ROW- FOR CHANGING ARTIST AND CONTACT ASSOCIATION
	$assQuery = "UPDATE artist_info SET contact_id='$_POST[contact_id]'WHERE artist_id='$_POST[artist_id]'";
	$contInfo = "select contact_name from contact_info where contact_id='$_POST[contact_id]'";
	$artInfo = "select artist_name from artist_info where artist_id='$_POST[artist_id]'";

	// PUT MYSQL QUERY RESULTS INTO ARRAYS
	$assup = mysql_query($assQuery) or die(mysql_error());
	$contRes = mysql_query($contInfo) or die(mysql_error());
	$artRes = mysql_query($artInfo) or die(mysql_error());

	// PULL NAMES FROM MYSQL RESULTS
	$contEntered = $contRes['contact_name'];
	$artEntered = $artRes['artist_name'];

	// PUT CHANGED INFO INTO NEW HTML BLOCK - SECOND TIME AROUND
	$html_variable = "<h1>Success!</h1>
					  <h2>Results:</h2>
					  <p> ".$artEntered."is now associated with
					  ".$contEntered." as their Contact</p>
					  <p>Click here to 
					  <a href=\"associate.php\">change more
					  </a> Artist / Contact associations</p>
					  <p>or go <a href=\"control.htm\">back to the main</a> control</p>";

	}// END IF LOGIC PART TWO
?>
<html>
<head>
<title>Change Associated Contacts and Artists</title>
<link rel="STYLESHEET" type="text/css" href="css/php.css">
</head>
<body>
<p>Results</p>
<?php echo $html_variable; ?>
</body>
</html>

thanks!

Rodney_H_

It may be as a result of your first if statement. You are comparing a value to something that may not be set yet. So, if you tweak it a little, it may work and display part one, with the form, which can then be submitted to execute your ifelse statements.

<?php
// if statement:
if (!isset($_POST['op']) || $_POST['op'] != "do_it") {
     // do stuff here
}

else if ($_POST['op'] == "do_it") {
     // do other stuff here
}
?>

ATS16805

the strangest thing is that even after fixing that line w/ the

if (!isset($_POST['op']) || $_POST['op'] != "do_it")

in place of the "undefined variable" , it still doesn't display that HTML Form. no matter what i've tried, i can't seem to get it to print the $variable holding the HTML form!

Rodney_H_

It took me some digging to figure it out. Let's look at your while loop:

<?php
while ($contArray = mysql_fetch_array($contShow) or die(mysql_error()) ) {
     // do stuff here
}
?>

Do you see? When the while loop is performing, it is storing the values into the variable for good measure. But then, when there are no more results, you are telling the whole script to die before anything is output onto the page.

So, you have already provided adequate mysql protection previous to this line, so just:

<?php
while ($contArray = mysql_fetch_array($contShow)) {
     // do stuff here
}
// and continue...
?>

PS: Your submit button needs an '=' (equal sign) at:

value="Assciate Contact & Artist Now" />

ATS16805

thanks, Rodney!! i knew it had to be something simple like that which i was just overlooking!
phew (wipes brow)

Rodney_H_

Yup. I know how you feel. I just had a similar URGH in my code, and it turned out to be something like this, too.

🙂

ATS16805

hmph!
i was so confident that this was in fact the solution that i may have spoke too soon!
here's an update on my script's current version, which reflects the modified WHILE loops, and i'm currently still not getting the <FORM> on output, but rathere my little "if loop test" output.

php IF tests failed. sorry, nothing stored in $outputhtml.
Results

Notice: Undefined variable: outputhtml in C:\Apache\Apache2\htdocs\wwwroot\Crowbar\web_app\associate.php on line 106

curious about this output. why does "Results", my HTML line <p>Results</p> display under the <?php echo...> line? is that a clue which might help to solve my problem?

if (isset ($_POST['op']) and ($_POST['op'] != "doit")) {
							  // BEGIN IF 'OP NOT EQUAL TO DO_IT' LOGIC

// BEGIN MAKING HTML BLOCK
	$outputhtml = "<h1>Associate Contact with Artist info</h1>
					  <p>Use the pull-downs to match Contact person
					  to the appropriate Artist</p>
					  <form method=\"post\" action=\"$_SERVER[PHP_SELF]\">
					  <p><select name=\"contact_id\">
					  <option value=\"\">-- Contact Name --</option>";

		// QUERY FOR CONCTACT ID AND NAME
		$contQuery = "select contact_id, contact_name from contact_info";
		$contShow = mysql_query($contQuery) or die(mysql_error());

	while ($contArray = mysql_fetch_array($contShow)) {
													// START WHILE LOOP ONE

		$contId = $contArray[0]; 
        $contName = $contArray[1];	

$outputhtml .= "<option value=\"$contId\">$contName</option>";

	}
	// END WHILE LOOP ONE

$outputhtml .= "</select></p>";

// QUERY FOR ARTIST ID AND NAME
$artQuery = "select artist_id, artist_name from artist_info";
$artShow = mysql_query($artQuery);

$outputhtml .= "<p>Use this pull-down to match an Artist 
                   with the Contact selected above</p>
				   <p><select name=\"artist_id\">
				   <option value=\"\">-- Artist Name --</option>";

	while ($artArray = mysql_fetch_array($artShow)) {
													// START WHILE LOOP TWO
		$artId = $artArray['artist_id'];
		$artName = $artArray['artist_name'];

	$outputhtml .= "<option value=\"$artId\">$artName</option>";

	}
	// END WHILE LOOP TWO

	// MORE HTML VARIABLE CONCAT
	$outputhtml .= "</select></p>";

	$outputhtml .= "<p>When you are finished making your selections
					   simply hit the button below, and your selections will
					   be associated properly for future reference</p>
					   <p>
					   <input type=\"submit\" name=\"submit\" 
					   value=\"Assciate Contact &amp; Artist Now\" /></p>
					   <p><input type=\"hidden\" name=\"op\" value=\"doit\" /></p>
					   </form>";


	}
	// IF LOGIC PART TWO SHOULD ACTIVATE UPDATE QUERY AND ASSOCIATE ARTIST AND CONTACT
	 else if (isset($_POST['op']) and ($_POST['op'] == "doit")) {

	// SQL -UPDATE ROW- FOR CHANGING ARTIST AND CONTACT ASSOCIATION
	$assQuery = "UPDATE artist_info SET contact_id='$_POST[contact_id]'WHERE artist_id='$_POST[artist_id]'";
	$contInfo = "select contact_name from contact_info where contact_id='$_POST[contact_id]'";
	$artInfo = "select artist_name from artist_info where artist_id='$_POST[artist_id]'";

	// PUT MYSQL QUERY RESULTS INTO ARRAYS
	$assup = mysql_query($assQuery) or die(mysql_error());
	$contRes = mysql_query($contInfo) or die(mysql_error());
	$artRes = mysql_query($artInfo) or die(mysql_error());

	// PULL NAMES FROM MYSQL RESULTS
	$contEntered = $contRes['contact_name'];
	$artEntered = $artRes['artist_name'];

	// PUT CHANGED INFO INTO NEW HTML BLOCK - SECOND TIME AROUND
	$outputhtml = "<h1>Success!</h1>
					  <h2>Results:</h2>
					  <p> ".$artEntered."is now associated with
					  ".$contEntered." as their Contact</p>
					  <p>Click here to 
					  <a href=\"associate.php\">change more
					  </a> Artist / Contact associations</p>
					  <p>or go <a href=\"control.htm\">back to the main</a> control</p>";


	}// END IF LOGIC PART TWO
	else { echo "php IF tests failed. sorry, nothing stored in \$outputhtml."; }
?>
<html>
<head>
<title>Change Associated Contacts and Artists</title>
<link rel="STYLESHEET" type="text/css" href="css/php.css">
</head>
<body>
<p>Results</p>
<?php 
echo "<p>".$outputhtml."</p>"; ?>
</body>
</html>

Rodney_H_

Well, I wasn't about to watch Desperate Housewives with everyone so, I tinkered and set up two tables in my system so I could simulate what you are doing and came up with this:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Change Associated Contacts and Artists</title>
<link rel="STYLESHEET" type="text/css" href="css/php.css">
</head>

<body>
<?php
// MAKE SQL CONNECTION
$conn = mysql_connect("localhost", "private", "private") or die(mysql_error());
// SELECT DB
$db = mysql_select_db("cb_shows1", $conn) or die(mysql_error());


// IF 'OP NOT EQUAL TO DO_IT'
if (!isset($_POST['submit']) || !isset($_POST['op'])) {

// QUERY FOR CONCTACT ID AND NAME
$contQuery = "SELECT contact_id, contact_name from contact_info";
$contShow = mysql_query($contQuery) or die(mysql_error());
?>
<h1>Associate Contact with Artist info</h1>
<p>Use the pull-downs to match Contact person to the appropriate Artist</p>
<form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>">
<select name="contact_id">
<option value="">-- Contact Name --</option>
<?php

// START WHILE LOOP ONE
while ($contArray = mysql_fetch_array($contShow)) {
	$contId = $contArray['contact_id'];
	$contName = $contArray['contact_name'];        
	echo '<option value="' . $contId . '">' . $contName . '</option>' . "\n";
}
?>
</select>

<p>Use this pull-down to match an Artist with the Contact selected above</p>
<select name="artist_id">
<option value="">-- Artist Name --</option>'
<?php

// QUERY FOR ARTIST ID AND NAME
$artQuery = "select artist_id, artist_name from artist_info";
//$artQuery = "SELECT * FROM books";
$artShow = mysql_query($artQuery) or die(mysql_error());	

// START WHILE LOOP TWO                       
while ($artArray = mysql_fetch_array($artShow)) {
	$artId = $artArray['artist_id'];
	$artName = $artArray['artist_name'];
	echo '<option value="' .$artId. '">' .$artName. '</option>' . "\n";
}
?>
</select>
<p>When you are finished making your selections simply hit the button below, 
and your selections will be associated properly for future reference</p>
<p><input type="submit" name="submit" value="Assciate Contact & Artist Now" /></p>
<input type="hidden" name="op" value="do_it" />
</form>
<?php
}

// ELSE the form has been submitted, process form:
else {
	if (isset($_POST['op']) &&  trim($_POST['op']) == "do_it") {
	// SQL -UPDATE ROW- FOR CHANGING ARTIST AND CONTACT ASSOCIATION
	$assQuery = "UPDATE artist_info SET contact_id='$_POST[contact_id]' WHERE artist_id='$_POST[artist_id]'";
	$contInfo = "SELECT contact_name FROM contact_info WHERE contact_id='$_POST[contact_id]'";
	$artInfo = "SELECT artist_name FROM artist_info WHERE artist_id='$_POST[artist_id]'";

// PUT MYSQL QUERY RESULTS INTO ARRAYS
$assup = mysql_query($assQuery) or die(mysql_error());
$contRes = mysql_query($contInfo) or die(mysql_error());
$artRes = mysql_query($artInfo) or die(mysql_error());

// PULL NAMES FROM MYSQL RESULTS
$contEntered = $contRes['contact_name'];
$artEntered = $artRes['artist_name'];

?>
<h1>Success!</h1>
<h2>Results:</h2>
<p><?php echo $artEntered; ?> is now associated with <?php echo $contEntered; ?> as  their Contact</p>
<p>Click here to <a href="associate.php">change more</a> Artist / Contact associations</p>
<p>or go <a href="control.htm">back to the main</a> control</p>
<?php
}
// else the form was submitted without op being set:
else {
	echo '<p>The form was submitted, but there was an error.  Please go back.</p>';
	}
}
?>

</body>
</html>

I hope this helps.

ATS16805

hey, Rodney, THANK YOU SO MUCH for taking the time away from Deperate Housewives (hehe) to look into this for me so closely as to even make a mock-up locally. that's AWESOME of you.

actually, in the meantime, i've been streamlining and fixing code on other pages in this app (the same one using this "associations" page), getting ready for final versioning-- and during this cleanup process, i discovered something about this Problem topic of this thread.

i discovered that by changing the

 if (isset ($_POST['op']) and ($_POST['op'] != "doit"))

back to my original way of

if ($_POST['op'] != "do_it")

(in both of the statments which used it) that the variable, now called $outputhtml, was NO LONGEER coming up empty! i don't understand yet because this (isset ($_POST['op']... ) was a recommendation from a forum user (in another php forum ... so, a big "booooo" to 'em 😉 ), and i still haven't got to research it at php.net yet (but i plan to).

so, long story short, my script worked after i made that change. however, i DO wish to examine what you've done here, and i'm sure i'll learn something, and maybe even switch to your script entirely for this page! why? because i like what you've done w/ the XHTML / PHP integration. did you KNOW i had an interest in Web Standards, or were you just "showing me the way to the light"?
🙂

i think this looks more like the direction i want to be going in, as i've been coding for XHTML compliancy, and the PHP/ HTML cohabitance on a single page model i've been following seems a bit cumbersome-- but it's what i learned from a PHP book, so hence why i've stuck w/ it.

anyway, thanks so much. i really appreciate it!!!

Rodney_H_

Hey, ATS16805, that is great. I am glad you got it going.

I am not sure why that other way didn't work. Hmm. Oh well. Research it and get back to me.

As far as xhtml, I have been converting friends to xhtml and css for about a year now after reading Eric Meyer's Book, so I am glad that you are considerate of web standards. Way to go! One for the team!!

Anyway, I was glad to help, or at least collaborate with you, seeing (from your web site) as how you are a musician too.

-Kind Regards