CREATE FUNCTION set_updated_at_to_now() RETURNS TRIGGER AS $$BEGIN
    NEW.updated_at = NOW();
    RETURN NEW;
END;$$ language PLPGSQL;
CREATE TABLE items (
    wikidataid TEXT NOT NULL,
    description TEXT NOT NULL,
    created_at TIMESTAMP WITH TIME ZONE DEFAULT now() NOT NULL,
    updated_at TIMESTAMP WITH TIME ZONE DEFAULT now() NOT NULL
);
CREATE INDEX tags_item_id_index ON tags (item_id);
CREATE INDEX tags_created_at_index ON tags (created_at);
CREATE TRIGGER update_tags_updated_at BEFORE UPDATE ON tags FOR EACH ROW EXECUTE FUNCTION set_updated_at_to_now();
CREATE INDEX items_created_at_index ON items (created_at);
CREATE TRIGGER update_items_updated_at BEFORE UPDATE ON items FOR EACH ROW EXECUTE FUNCTION set_updated_at_to_now();
ALTER TABLE tags ADD CONSTRAINT tags_ref_item_id FOREIGN KEY (item_id) REFERENCES items (id) ON DELETE CASCADE;