create table public.campaigns (
    id uuid primary key default gen_random_uuid(),
    created_at timestamp with time zone not null default now(),
    brand_id uuid not null references public.brands(user_id) on delete cascade,
    description text not null default ''::text
);
alter table public.campaigns enable row level security;
create policy everyone_view_only
    on public.campaigns
    as permissive
    for select
    to authenticated, anon
    using (true);
create policy users_manage_their_own_data
    on public.campaigns
    as permissive
    for all
    to authenticated
    using ((( SELECT auth.uid() AS uid) = brand_id));