Mimicking a filesystem using PostgreSQL and LTree: how to write a query to insert multiple nodes at once

I'm struggling with how to insert a recursive materialised path using one transaction.

This is the situation:I'm trying to mimic a filesystem of folders and files. I have a table representing nodes using the materialised path approach. The path is materialised using the LTree extension for search reasons.

This is the table definition and some records as sample data.

CREATE EXTENSION IF NOT EXISTS ltree WITH SCHEMA public;CREATE TABLE public.node_document (    id bigint NOT NULL,    name character varying(2048) NOT NULL,    path public.ltree,    is_container boolean,    parent_node_id bigint,    domain_id bigint NOT NULL);CREATE SEQUENCE public.path_tree_id_seq    START WITH 1    INCREMENT BY 1    NO MINVALUE    NO MAXVALUE    CACHE 1;ALTER SEQUENCE public.path_tree_id_seq OWNED BY public.node_document.id;ALTER TABLE ONLY public.node_document ALTER COLUMN id SET DEFAULT nextval('public.path_tree_id_seq'::regclass);INSERT INTO public.node_document (id, name, path, is_container, parent_node_id, domain_id) VALUES(1, 'root', 'root', True, 1, 1),(2, 'tom', 'root.tom', True, 1, 1),(3, 'karamel', 'root.tom.karamel', True, 2, 1),(4, 'files', 'root.tom.karamel.files', True, 3, 1),(5, 'document', 'root.tom.karamel.files.document', False, 4, 1);

One requirement that I'm struggling with is to insert a new file recursively.

As an example, suppose I want to insert root.tom.karamel.files.folder1.file1using one transaction, this means that I need to insert each individual (new) node into the database and take the primary key of the parent node and put it as a foreign key of the actual node to ensure referential integrity.

This is what I've came up with so far:

WITH requested_path(node_ltree, node_name) AS (    VALUES    (text2ltree('root'), 'root'),    ('root.tom', 'tom'),    ('root.tom.karamel', 'karamel'),    ('root.tom.karamel.files', 'files'),    ('root.tom.karamel.files.folder1', 'folder1'),    ('root.tom.karamel.files.folder1.file1', 'file1')),deepest_existing_path AS (    SELECT path, name     FROM node_document    WHERE path @> 'root.tom.karamel.files.folder1.file1' AND is_container),records_to_insert AS (    SELECT *    FROM requested_path    EXCEPT    SELECT *    FROM deepest_existing_path)SELECT * FROM records_to_insert

As you can see, I've managed to identify the individual nodes that should be inserted, but I'm stuck by inserting them using the primary key of the parent as the foreign key in the actual node.

I think I would need a recursive insert CTE or use PLSQL, but I'm not sure. I think an recursive insert CTE is more performant because it would be pure SQL, but I'm not sure.

Could anyone please help me out?