Recursive function help

[Anon]

I'm building a simple nested category system on a database... shouldn't be too difficult. I've done it before but I can't find the code and I'm having a huge problem trying to figure out how to get an array of parents off a category. Here is the database:

fileCategories:
catID int not null primary key auto_increment
catName varchar(32) not null
catDescription text not null
catParent int not null

So basically, catParent will contain a catID of it's parent category, or zero(0) if it's a root category.

So say I have the following values inside the table at this point (format: catID : catName : catParent):

1 : Games : 0 // root category
2 : Quake : 1 // under "Games"
3 : Half-Life : 1 // under "Games"
4 : Movies : 2 // under "Games" -> "Quake"
5 : Movies : 3 // under "Games" -> "Half-Life"
6 : Gameplay : 4 // Under "Games" -> "Quake" -> "Movies"
7 : Trailers : 4 // Under "Games" -> "Quake" -> "Movies"

So what I want to do, when calling a function and passing a catID, is get an array with all the categories above it.

So, say I call getCategories(7), I would expect an array with something like:

[0] -> "Games"
[1] -> "Quake"
[2] -> "Movies"
[3] -> "Trailers"

But I'm having a problem designing the recursive function that will do this. Any help would be greatly appreciated.

[cordex]

function easyrecursive($aid,$array='')
{
$sel_st = "SELECT * FROM fileCategories WHERE catID='$aid'";
$sel_rs = mysql_query($sel_st);
$sel_ar = mysql_fetch_array($sel_rs);
if($sel_ar[catParent] != 0)
{
$array[] = $sel_ar[catName];
easyrecursive($sel_ar[catParent], $array)
}
else
{
$array[] = $sel_ar[catName];
$array = array_reverse($array);
return($array);
}
}

$array = easyrecursive(7);

[Anon]

Hi,

I appreciate the help, but it's not quite working correctly. There's a problem with the return($array) - it always returns an empty value... If I read all the values to a global array, and I don't return anything, it seems to work.

I guess I don't get how this line is supposed to work:

easyrecursive($sel_ar[catParent], $array);

If you're returning a value in the function, this line doesn't do anything with the returned value, so how can it be correct?

Argh, my head hurts 🙁

[Anon]

//Cheap Db App Layer
$sqlmenu -> Query ("SELECT * from tblcategory order by subcategory_name");
while ($sqlmenu -> ReadRow()) {
$tmpArray[$sqlmenu -> RowData["subcategory_parent"]][$sqlmenu -> RowData["subcategory_id"]] = $sqlmenu -> RowData["subcategory_name"];
}
$sqlmenu ->Close;

function sortCategories(&$inAry, &$outAry, $level, $indent) {
if( is_array($inAry[$level]) ) {
while( list($id, $name) = each($inAry[$level]) ) {
$outAry[$id] = "$indent $name";

sortCategories($inAry, $outAry, $id, "$indent $name > ");
}
}
}

// Just replace the '0' with the starting point ie. '7'
sortCategories($tmpAry, $ary, 0, "");

Hope this helps. If it doesn't just drop me a email and try sort you out

[Anon]

Bah, you're right. Try this:

function easyrecursive($aid,$array='')
{
$sel_st = "SELECT * FROM fileCategories WHERE catID='$aid'";
$sel_rs = mysql_query($sel_st);
$sel_ar = mysql_fetch_array($sel_rs);
if($sel_ar[catParent] != 0)
{
$array[] = $sel_ar[catName];
$array=easyrecursive($sel_ar[catParent], $array)
return($array);
}
else
{
$array[] = $sel_ar[catName];
$array = array_reverse($array);
return($array);
}
}

[Anon]

After I posted my comment about how it didn't work, I spent the night coming up with this. It's basically the same as the one you posted after but a couple of small differences.

Thanks for all the help, I really appreciate it.

function getParents($catID, $array = NULL) {
$q = "select * from fileCategories where catID = $catID";
$r = mysql_query($q);
if(!$r) {
echo mysql_error();
}
else {
$a = mysql_fetch_array($r);
$array[] = $a['catName'];
if($a['catParent'] == 0) {
return array_reverse($array);
}
else {
$array = getParents($a['catParent'], $array);
return $array;
}
}
}