Tracking Likes in Postgres

When I started writing Devy, I focused on using tools I wanted to get better at. The project was primarily a way for me to learn.

ALTER TABLE post ADD COLUMN IF NOT EXISTS like_count integer DEFAULT 0;

CREATE OR REPLACE FUNCTION update_like_count() RETURNS TRIGGER AS $$
BEGIN
    IF TG_OP = 'INSERT' THEN
        UPDATE "post"
        SET like_count = like_count + 1
        WHERE id = NEW.post_id;
    ELSIF TG_OP = 'DELETE' THEN
        UPDATE "post"
        SET like_count = like_count - 1
        WHERE id = OLD.post_id;
    END IF;
    RETURN NULL;
END;
$$ LANGUAGE plpgsql;

CREATE OR REPLACE TRIGGER trigger_update_like_count
AFTER INSERT OR DELETE ON "like"
FOR EACH ROW
EXECUTE FUNCTION update_like_count();