CREATE TABLE node (
		id SERIAL NOT NULL PRIMARY KEY,
		person_id INT NOT NULL REFERENCES person(id),
		thread_id INT NOT NULL REFERENCES node(id),
		parent_id INT REFERENCES node(id),
		title VARCHAR(80),
		text TEXT,
		creation_time TIMESTAMP NOT NULL DEFAULT NOW(),
		karma INT NOT NULL DEFAULT 0,
		category_id INT NOT NULL REFERENCES category
		);