使用postgres触发器高效更新标签计数

CREATE OR REPLACE FUNCTION update_tag_count()
RETURNS TRIGGER AS $$
BEGIN
    IF TG_OP = 'INSERT' THEN
        -- 在计数表中增加对应标签的计数
        UPDATE tag_count SET count = count + 1 WHERE tag = NEW.tag;
    ELSIF TG_OP = 'UPDATE' THEN
        -- 在计数表中更新对应标签的计数
        UPDATE tag_count SET count = count + 1 WHERE tag = NEW.tag;
        UPDATE tag_count SET count = count - 1 WHERE tag = OLD.tag;
    ELSIF TG_OP = 'DELETE' THEN
        -- 在计数表中减少对应标签的计数
        UPDATE tag_count SET count = count - 1 WHERE tag = OLD.tag;
    END IF;
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;

CREATE TRIGGER update_tag_count_trigger
AFTER INSERT OR UPDATE OR DELETE ON tags
FOR EACH ROW
EXECUTE FUNCTION update_tag_count();