$row=mysql_fetch_array($result)

[seanpaulcail]

Okay to start off this query we bigin with

PART1

$query = "select catid, catname from categories";
result=mysql_query($query);

simple enough

Part2.

then the result is passed to a function which follows

function db_result_to_array($result)
{
res array=array();
for ($count=0; row=@mysql_fetch_array($result); count++)
$res_array[$count]=$row;

return res_array;
}

Please explain part 2 in detail.

I do not understand the for statement or the $res_array [$count] = $row.

I have researched this but it is the only code that troubles me. The code works just fine I just don't understand it

Then Part 3.

$cat_array=$res_array

for each ($cat_array as $row)
{
$url="show_cat.php?catid=".($row["catid"]);
$title = $row["catname"];
echo "<li>;
do_html_url($url, $title);
}

I will betterunderstand Part3 if I can understand part 2.
Please explain part 2

[keith73]

What part 2 is doing is reading the result into a 2-dimensional array. Part 3 is stepping through the 2D array and getting the values from it. A 2D array is an array that contains arrays.

It all can be neatly done in less code though. Instead of reading it to a 2D array, just run a while loop on the result.

while($row = mysql_fetch_array($result)){
	$url="show_cat.php?catid=".($row["catid"]);
	$title = $row["catname"];
	echo "<li>;
	do_html_url($url, $title);
} 

you could further optimize it by not calling the do_html_url function or setting 2 new variables (title,url) and just output the html in the loop.

while($row = mysql_fetch_array($result)){
	echo "<li><a href=\"show_cat.php?catid=".($row["catid"]) . "\">" .
	     $row['catname'] . "</a></li>\n";
} 

Does this help?

• Keith

[seanpaulcail]

I understand your explanation but

I need to know exaclty everything to truly understand. Otherwise I feel that I am operating
blindly

This two "dimensional array that contains array" is understood but could you be more
detailed: what is the main array, what is each other array within this array.

please explain $row=my_sql_fetch_array($result).

I understand that "my_sql_fetch_array" creates a numeric and associative array. BUt what
exactly does $row now equal.

Also I am not clear on $res_array[$count]=$row.

What does this do.

Thanks again

[ahundiak]

You might want to read the section on arrays in the php manual. It takes quite a few words to completely describe what is happening in this code.

[seanpaulcail]

I've read everything from my 2 PHP books to PHP.net
but I'm still in a fog.

[ahundiak]

I know the fog feeling.

$row is a single dimension array representing one record in the database. So you can do thing like
echo $row['catid'],$row['catname'];

In other words, you can get to all the individual columns for the record.

In most cases, you process one row then discard it.
The classic
while($row = mysql_fetch_array($result))
{
echo $row['catname'];
}

But sometime you need to deal with all of the records returned from a query. Maybe you need to sort them using a custom function that sql does not support. Or maybe you need to generate some summarization data.

In this case, what you probably want to do is to create an array holding all the rows in the query. It will be an array of arrays. That's what $res_array is.

Hope this helps.

By the way, you can use print_r($row) to dump an array out to the browser. Sometimes it helps to see the internals.

[seanpaulcail]

Thanks

[seanpaulcail]

res_array euals:

ArrayArray
( [0] => Array
( [0] => 1 [catid] => 1 [1] => Internet [catname] => Internet )

[1] => Array
( [0] => 2 [catid] => 2 [1] => Self-help [catname] => Self-help )

[2] => Array
( [0] => 5
[catid] => 5 [1] => Fiction [catname] => Fiction )

[3] => Array
( [0] => 4 [catid] => 4 [1] => Gardening [catname] => Gardening ) )

So it looks l;ike we have a three dimensional array.

Is this necessary?