这是Mysql外键的工作吗?

In the past few years I have read plenty of articles on Foreign Keys in MySQL, nothing recent though. I know they are good to use on something like a forum topic that has child post's under it, if I delete a topic with 100 post's connected to that topic, foreign keys will make it delete those 100 topics for me, am I correct so far? In the past few years I have read plenty of art