Where does the $row variable come from?

Can someone please explain the parts in this script that I don't understand? Please don't refer me to the PHP manual cause I looked through it and I don't understand where some of the variables come from. I will comment the parts I don't understand in blue.

<?php
mysql_connect("localhost", "phpuser", "alm65z");
mysql_select_db("phpdb");
//I know I use it in all other PHP/MySQL commands but what is the value of $result?
$result = mysql_query("SELECT * FROM usertable");
//I think this is saying if $result isset and there are rows in the database then execute
if ($result && mysql_num_rows($result)) {
$numrows = mysql_num_rows($result);
$rowcount = 1;
//Okay. This is where I don't understand. It's saying that loop as long as $row = mysql_fetch_assoc($result). I don't know where they got $row from or what the value of mysql_fetch_assoc($result) equals.
while ($row = mysql_fetch_assoc($result)) {
print "Row $rowcount<br />";
//And another loop... I don't know where the variables ($var, $val, and $row) come from. I also don't know how they are doing what they are doing here, but I'm pretty sure I can figure it out if I knew where the variables came from. I figure they are printing $var and $val to the screen.
while(list($var, $val) = each($row)) {
print "<B>$var</B>: $val<br />";
}

print "<br />";
++$rowcount;
}
}
?>

Thanks.

~imozeb

 

I'll give it a go...

<?php
mysql_connect("localhost", "phpuser", "pass");
//These are your login details, I strongly recommend removing your password when posting online...

mysql_select_db("phpdb");

$result = mysql_query("SELECT * FROM usertable");
//Select all the entries within usertable, result is all of this information

if ($result && mysql_num_rows($result))
// If result is set and there are rows in the database
{
	$numrows = mysql_num_rows($result);
	//Counts the number of rows in the database
	
	$rowcount = 1;
	//Sets rowcount to equal 1
	
	while ($row = mysql_fetch_assoc($result))
	// Loops through the row from the table that are in result, as set above
	{
		print "Row $rowcount<br />";
		//Print row count
		
		while(list($var, $val) = each($row))
		// Sets the first column from the table as $var and the second column as val, loops through each row of the database showing these values onscreen from print
		{
			print "<B>$var</B>: $val<br />";
		}
	
		print "<br />";
		
		++$rowcount;
		//increases the counter by one to tell the program to get the information from the next row in the datbaase
		
	}
}
?> 

PHP:

 

So $rowcount is just a variable to tell the user what row the data came from, it doesn't serve any other function, so I could delete it with no problem?

And...

while($row = mysql_fetch_assoc($result))

...since it is only using one equals sign is it setting $row to equal mysql_fetch_assoc($result) and... since it is using while it loops until there are no mysql_fetch_assoc($result) (which are rows) left? Am I right?

By the way thanks Silver89, you explained it really well.

~imzoeb

 

You cannot delete $rowcount = 1. If you do, you will get an error later, when the program tries to print the value of $rowcount (print "Row $rowcount<br />"
$rowcount = 1; sets the variable for future use.

 

- yes you can remove the rowcount without causing problems.

- yes you are correct, it will fetch each row, put it into the $row variable, execute the code in the loop then get the next row. When there is no rows left to be fetched, $row will equal null which will end the loop.