Create Multidimentional json object from database - php

Question

i'm having some troubles creating a multidimentional JSON object in PHP.
My Postgresql database looks like this:
Id Name Parent
1 Active NULL
2 Passive NULL
3 Fixed 1
4 Dynamic 3
5 Taxes 2
6 Fair 2
...
The parent column is linked with the Id in the first column
What i want to accomplish is this:
[
{
"name": "Active",
"children": [
{
"name": "Fixed",
"children": [
{
"name": "Dynamic",
"children": NULL
}
]
}
]
},
{
"name": "Passive",
"children": [
{
"name": "Taxes",
"children": NULL
},
{
"name": "Fair",
"children": NULL
}
]
}
]
So first of all i FETCH the data out of our database with
$result = fetchAll(PDO::FETCH_OBJ); // fetches every row in an object
i could send this result to the frontend (javascript) and convert this data to JSON there but then i send the column names with it and i don't think that is a good idea in security terms.
First of all i want to make the top level of the JSON file. With the help of this topic Object to array in PHP i manage to put that together:
$mainArray = [];
foreach ($result as $value) {
if ($value['Parent'] === NULL) {
$object = new stdClass();
$object->name = $value['Name'];
$object->children = [];
$mainArray[] = $object;
}
}
This is my result:
[
{
name: "Actief",
children: [ ]
},
{
name: "Passief",
children: [ ]
}
]
But i'm stuck adding children to the correct parent. I just can't seem to find how to do it.
I need to do something like this:
Add Fixed to Object where Object->Name is 1 = Active.

Answer 1

This will do the job. Assuming your child data won't come before your parent data.
$mainArray = [];
foreach ($result as $key=>$value) {
if ($value['Parent'] === NULL) {
$object = new stdClass();
$object->name = $value['Name'];
$mainArray[$value['Id']] = $object;
}else{
$childOBJ = new stdClass();
$childOBJ->name = $value['Name'];
$mainArray[$value['Parent']]->children[] = $childOBJ;
}
}
$finalArray = array_values($mainArray); // changes to indexed array for json purpose
UPDATE: WITH RECURSION and refrence
function makeTree($result, $parentId=NULL){
$tree = [];
foreach ($result as $value) {
if($value['Parent'] == $parentId){
$object = new stdClass();
$object->name = $value['Name'];
$child = makeTree($result, $value['Id']);
if($child){
$object->children=$child;
}
$tree[] = $object;
}
}
return $tree;
}
$finalArray = makeTree($result);