Create JSON tree from database in Django

I need to create JSON file to reflect tree structure in Python / Django.

I have two options - call database on creating each node of tree or extract data from database all at once and create tree afterwards. I think calling database on each node for thousands of data would be a slow task, so decided to create raw JSON data from database at first and then next create JSON tree. I created raw JSON data from database [PostgreSQL]. The raw JSON data looks like:

[{"Name": "Michael Andrew", "class": "A", "order": "B", "family": "C"}, {"Name": "John Belew", "class": "A", "order": "D", "family": "E"}, {"Name": "Warren Noah", "class": "F", "order": "G", "family": "H"}]

I want following JSON tree to be made from the data above in Django / Python:

    {
"name": "jsontree",
"children":[
{
    "name": "A",
    "children": [
    {
        "name": "B",
        "children": [
        {
            "name": "C",
            "children": [
            {
                "name": "Michael Andrew"
            }]
        }]
    },
    {
        "name": "D",
        "children": [
        {
            "name": "E",
            "children": [
            {
                "name": "John Belew"
            }]
        }]
    }]

},
{
    "name": "F",
    "children": [
    {
        "name": "G",
        "children": [
        {
            "name": "H",
            "children": [
            {
                "name": "Warren Noah"
            }]
        }]
    }]
}]
    }

What may be the efficient way to do so in Python? I heard of django-mptt to create JSON tree from database but have no idea about what it actually is.