Preparation for special nodes

sql/00009.sql

@@ -0,0 +1,35 @@
+-- Special node such as orphaned and deleted nodes.
+ALTER TABLE public.node ADD special bool DEFAULT false NOT NULL;
+
+
+-- Needs to be dropped in order to drop the index on UUID.
+ALTER TABLE public.node DROP CONSTRAINT node_node_fk;
+
+-- Index was missing user ID.
+DROP INDEX public.node_uuid_idx;
+CREATE UNIQUE INDEX node_user_uuid_idx ON public.node (user_id,"uuid");
+
+-- Restore the "foreign" key of parent UUID back to UUID.
+ALTER TABLE public.node ADD CONSTRAINT node_node_fk FOREIGN KEY (user_id,parent_uuid) REFERENCES public.node(user_id,"uuid") ON DELETE RESTRICT ON UPDATE RESTRICT;
+
+
+-- Auto-create the special nodes for each user.
+CREATE OR REPLACE FUNCTION create_user_nodes()
+RETURNS TRIGGER AS $$
+BEGIN
+	-- NEW holds the row being created.
+	-- No semi-colons omitted here, PL/pgSQL requires them.
+	INSERT INTO public.node (user_id, uuid, parent_uuid, special, name)
+	VALUES
+		(NEW.id, '00000000-0000-0000-0000-000000000000'::uuid, null, true, 'Start'),
+		(NEW.id, '00000000-0000-0000-0000-000000000001'::uuid, null, true, 'Orphaned nodes'),
+		(NEW.id, '00000000-0000-0000-0000-000000000002'::uuid, null, true, 'Deleted nodes');
+
+	RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE TRIGGER trg_after_user_insert
+AFTER INSERT ON public.user
+FOR EACH ROW
+EXECUTE FUNCTION create_user_nodes();