Creating an array using recursive php from mysql

问题:

I need to create an array from a mysql database organized like so

id    description    parentId    
1      Level 1        0           
2      Level 2        0           
3      Level 1a       1   
4      Level 1b       1 
5      Level 1a1      3
6      Level 1a1a     5

So that the output is like this:

Level 1
      Level 1a
           Level 1a1
                Level 1a1a
      Level 1b
Level 2

However my current code only outputs to the second level and then makes every other child it's own parent. Below is the current code:

$query = "SELECT * FROM pB_test ORDER BY parentId ASC";
$result = mysql_query($query) or die ('Database Error (' . mysql_errno() . ') ' . mysql_error());

$tree = array();

while($row = mysql_fetch_assoc($result)) 
{
    if($row['parentId'] == 0) 
    {
        $row['Children'] = array();
        $tree[$row['id']] = array(
                                'id' => $row['id'], 
                                'description' => $row['description'], 
                                'parentId' => $row['parentId']
                            );
    } 
    else 
    {
        $tree[$row['parentId']]['Children'][$row['id']] = $row['description'];
    }
}

$count = array_keys($tree);

foreach ($count as $array)
{
    ksort($tree[$array]['Children']);
}

echo print_r($tree, true);

Any help or nudge in the right direction would be great. Cheers

Update: Working Code

    $results = array();
while($row=mysql_fetch_assoc($dbresult)) 
{ 
    $results[]=$row;

    $tree = null;
foreach($results as $result)
{
    $thisref = &$refs->{$result['id']};
    foreach($result as $k => $v)
    {
        $thisref->{$k} = $v;
    }
    if ($result['parentId'] == 0) {
        $tree->{$result['id']} = &$thisref;
    } else {
        $refs->{$result['parentId']}->children->{$result['id']} = &$thisref;
    }
}

$tree; // contains the newly sorted tree.

}

print_r($tree);

回答1:

I found this code for grouping parent child arrays to be amazing. I have tested in 4 depths with no issue what so ever. It isn't a recursive function though.

$tree = null;
foreach($results as $result)
{
    $thisref = &$refs->{$result['id']};
    foreach($result as $k => $v)
    {
        $thisref->{$k} = $v;
    }
    if ($result['parentId'] == 0) {
        $tree->{$result['id']} = &$thisref;
    } else {
        $refs->{$result['parentId']}->children->{$result['id']} = &$thisref;
    }
}

$tree; // contains the newly sorted tree.

You may have to do some modification for it to fully work with your situation. But basically it loops through all the results and combines them by reference.

Do note that the ending $tree data type is an object and not an array

Good Luck

UPDATE

You can create the array as such

$query = "SELECT * FROM pB_test ORDER BY parentId ASC";
$dbresult = mysql_query($query) or die ('Database Error (' . mysql_errno() . ') ' . mysql_error());

$results = array();
while($row=mysql_fetch_assoc($dbresult)) 
{ 
    $results[]=$row 
}

回答2:

It would probably be easiest if you created an array that mapped from id to object as you create your objects so you can easily lookup nested objects. Basically:

$tree = array();
$lookup = array();

while($row = mysql_fetch_assoc($result))  
{
    $object = array('id' => $row['id'],        
                    'description' => $row['description'],        
                    'parentId' => $row['parentId']);

    $lookup[$row['id']] = $object;

    $parentId = $row['parentId'];
    if ($parentId == 0)
    {
        $tree[] = $object;
    }
    else
    {
        $lookup[$parentId]['Children'][] = $object;
    }
}