How to reference query values in Postgres res policy - postgresql

Question

I am trying to build a system with Postgres in which users can connect with each other by sending requests. I am handling the security logic with RLS. However, I am having some trouble with the structure of one of my policies.
Here are the tables of concern, stripped of any nonessential columns:
CREATE TABLE profile (
id UUID PRIMARY KEY,
name text
);
CREATE TABLE request (
id serial PRIMARY KEY,
sender_id UUID,
recipient_id UUID
);
CREATE TABLE connection (
id serial PRIMARY KEY,
owner_id UUID,
contact_id UUID
);
Users are only allowed to add a connection if:
There is a row which references their profile id in recipient_id in the request table.
There is no existing connection that involves both users (no matter which one is the owner_id and which is the contact_id)
Here is the Policy I've written:
CREATE POLICY "Participants INSERT" ON public.connection FOR
INSERT
WITH CHECK (
auth.uid() = owner_id
AND NOT EXISTS(
SELECT
*
FROM
public.connection c
WHERE
(
(
c.owner_id = owner_id --> Problem: How to reference query
AND c.contact_id = contact_id
)
OR (
c.contact_id = owner_id
AND c.owner_id = contact_id
)
)
)
AND EXISTS(
SELECT
*
FROM
public.request r
WHERE
(
r.sender_id = contact_id
AND r.recipient_id = owner_id
)
)
);
However, whenever I try to create a contact with a user whose id is already present in any row in the connection table (irrespective if it exists together with the correct contact_id), I get a policy violation error.
I think I might be referencing owner_id and contact_id wrong in the subquery because if I replace them manually with the appropriate id as a string, it works.
I'd really appreciate everyones input.

Answer 1

I found the answer. The parent query can be accessed through the name of the table. So all I had to do was to access owner_id and contact_id like this:
connection.owner_id
connection.contact_id
On a side-note: The query values can NOT be accessed like this:
public.connection.owner_id
public.connection.contact_id