how do i reference a parent id ?

[ricky spires]

hello.

 

say i have list and i want the correct children under each parent

 

so i have

$id

$parent_id

$type

$name

 

in the db i have

4 parents each with 2 children

 

id=1 - type=parent - parent_id=0 - name=p1

id=2 - type=parent - parent_id=0 - name=p2

id=3 - type=parent - parent_id=0 - name=p3

id=4 - type=parent - parent_id=0 - name=p4

id=5 - type=child - parent_id=1 - name=c1

id=6 - type=child - parent_id=1 - name=c2

id=7 - type=child - parent_id=2 - name=c3

id=8 - type=child - parent_id=2 - name=c4

id=9 - type=child - parent_id=3 - name=c5

id=10 - type=child - parent_id=3 - name=c6

id=11 - type=child - parent_id=4 - name=c7

id=12 - type=child - parent_id=4 - name=c8

 

so how would i do the code?

 

i thought i could do it like this but its not working.

 

<?php

$family = Family::find_all();
foreach($family as $familys){

$id = $familys->id;
$type = $familys->type;
$parent_id = $familys->parent_id;
$name = $familys->name;


echo'
<ul>';
if($type == "parent"){
echo $name;
} 
echo' </ul>


<li>';
if($type == "child" && $parent_id == $id){
echo $name;
} 
echo' 
</li>';
}
?>

 

 

all i get back is

 

    p1

 

    p2

 

    p3

 

    p4

 

 

no children

 

??

 

 

 

if i remove

$parent_id == $id

from

if($type == "child" && $parent_id == $id){

 

i get this

 

    p1

 

    p2

 

    p3

 

    p4

 

c1

 

c2

 

c3

 

c4

 

c5

 

c6

 

c7

 

c8

 

but they are not listed under the correct parent

 

 

 

 

 

i also tried moving the </ul> to the bottom but i get the same

<?php

$family = Family::find_all();
foreach($family as $familys){

$id = $familys->id;
$type = $familys->type;
$parent_id = $familys->parent_id;
$name = $familys->name;



echo'
<ul>';
if($type == "parent"){
echo $name;
} 
echo'


<li>';
if($type == "child"){
echo $name;
} 
echo' 
</li>
</ul>';
}
?>

 

 

 

any thoughts?

 

thanks

 

rick

[dzelenika]

This is not so simple as you tried.

You need two nested loops, outer one for parents the one and inner one for children of selected parent

 

 

[ricky spires]

thanks.

 

ill have another go and post my code

 

[AyKay47]

really, this could/should be done with your query, can you post the relevant class/method code.

[ricky spires]

sorry but could you give an example please.

 

 

this is my query

 

public static function find_all(){
	global $database;
	$sql = "SELECT * FROM ".self::$table_name."";
	return self::find_by_sql($sql);
}

thanks

[mikosiko]

you are implementing an "Adjacency List"; this query let you get the children of a node.

 

SELECT t1.id, t1.name, t2.id, t2.name
     FROM your-table AS t1
     LEFT JOIN your-table AS t2
          ON t2.parent_id = t1.id

[ricky spires]

i've done it

 

public static function find_all(){
	$sql = "SELECT * FROM ".self::$table_name."";
	return self::find_by_sql($sql);
}


public static function find_by_parent($parent_id){
	$sql = "SELECT * FROM ".self::$table_name."  WHERE parent_id=".$parent_id."";
	$result_array = self::find_by_sql($sql);
	return $result_array;
}

<?php

$family = Family::find_all();
foreach($family as $familys){

$parent_id = $familys->id;
$type = $familys->type;
$name = $familys->name;



echo'
<ul>';
if($type == "parent"){
echo $name;
} 
echo'


<li>';

	$child = Family::find_by_parent($parent_id);
	foreach($child as $childs){	
	$child = $childs->name;
	echo $child;
	} 
echo' 
</li>
</ul>';
}
?>

 

that echos

 

    p1

    c1c2

 

    p2

    c3c4

 

    p3

    c5c6

 

    p4

    c7c8

 

 

thanks all

 

 

p.s

 

mikosiko = your way looks interesting. im not sure if i fully understand what your doing but if it can be used to make my code better i would love to see it.

thanks